FREE 5-Ingredient Recipe EBook

• Why You Need My Chicken Zucchini Casserole
• Ingredients & Substitutions
• How To Make Chicken Zucchini Casserole
• My Recipe Tips
• Storage & Meal Prep
• More Cheesy Casserole Recipes
• Tools I Use For This Recipe
• Chicken Zucchini Casserole Recipe card
• Gratitude Moment
• Recipe Reviews

Casseroles are some of my favorite healthy dinners because you only need to make one dish—no need for a separate main and side. And even though my chicken zucchini casserole has some pre-cooking steps (as casseroles often do), I still love the simplicity of this one-recipe meal. And the perfect excuse to use more zucchini . And the cheesy gruyere sauce that totally feels like comfort food. Make it with me and make the most of zucchini season!

Why You Need My Chicken Zucchini Casserole

• Luscious gruyere cheese sauce – The sauce is what sets this one apart from your run-of-the-mill chicken casserole. You’ll love the rich, cheesy, and bold flavor! It doesn’t look like a lot of sauce because the veggies absorb some of it, but make no mistake, you can taste it in every bite!
• Never watery – If you’ve made my standalone zucchini casserole before, you know I won’t settle for anything less. This time I use a different method, but the texture is just as important. Don’t miss my tips below!
• Easy, healthy meal – The steps are straightforward, the ingredients are fresh and simple, and it’s packed with protein and veggies. Plus, it’s meal prep friendly, so you can even enjoy my chicken zucchini casserole on busy weeknights. You don’t need any sides, but you could start with a soup or salad , or finish off your meal with my summery cherry crisp .

Ingredients & Substitutions

Here I explain the best ingredients for my chicken zucchini casserole recipe, what each one does, and substitution options. For measurements, see the recipe card .

Main Ingredients:

• Chicken – I usually use boneless skinless chicken breast, but boneless chicken thighs also work. Cut the chicken into 1-inch pieces. Or if you’ve got leftover chicken bites , Instant Pot shredded chicken , or even a rotisserie chicken, feel free to use those — and save time by skipping the pan searing step.
• Vegetables – I used sautéed mushrooms, onions, and of course, zucchini. Yellow squash actually works just as well instead of zucchini. You can also toss in bell peppers or broccoli if you like.
• Olive Oil – For searing the chicken and sauteing the veggies. Avocado oil works just as well.
• Sea Salt & Black Pepper

VARIATION: Add garlic for more flavor!

I didn’t add garlic in my casserole, but feel free to add 2-4 cloves of minced garlic—just sauté them with the onions and mushrooms.

Cheese Sauce:

• Shredded Cheese – The star of my chicken zucchini casserole is the Swiss Gruyere cheese blend! I love the nutty, slightly sweet flavor. If you can’t find a blend, you can just shred both cheeses yourself. If you prefer a milder flavor, swap in a combo of parmesan and mozzarella cheese instead.
• Heavy Cream – This makes the sauce rich and creamy. If you’re looking for a lighter option, you can substitute with half-and-half or whole milk, but the sauce will be less thick.
• Chicken Broth – You can use my homemade chicken broth or a reduced-sodium store-bought version . If all you have is regular, I recommend using less salt on your chicken and veggies.
• Sour Cream – For more richness and tang. Greek yogurt works well as a substitute. Cream cheese can also work, but you might need a splash of extra cream, since it’s thicker.

How To Make Chicken Zucchini Casserole

I have step-by-step photos here to help you visualize the recipe. For full instructions with amounts and temperatures, see the recipe card .

1. Season & dry the chicken. Place the chicken pieces in a large bowl and pat dry with paper towels. Season with salt and pepper.
2. Cook the chicken. Heat olive oil in a large skillet over medium-high. Add the chicken pieces and sear, turning to brown all sides until cooked through. Transfer to a bowl and cover to keep warm.

1. Sauté the mushrooms & onions. Add more olive oil to the pan, reduce the heat, and add the mushrooms and onions. Cook until the mushrooms are soft and there is no liquid in the pan.
2. Cook the zucchini. Turn the heat to medium-high again, add the zucchini, and season with salt and pepper. Sauté until soft and slightly browned, then drain any remaining liquid. Transfer to the bowl with the chicken and set aside.

1. Make the sauce. While your oven preheats, add the heavy cream and chicken broth to the same skillet. Scrape up any browned bits with a wooden spoon. Simmer for about 5 minutes, until the sauce coats the back of a spoon. Then, stir in shredded cheese, until melted.

1. Assemble & bake. Pour the sauce into the bowl with the chicken and veggies. Mix to combine, then transfer the mixture to a small baking dish ( I use this one and it’s the perfect size). Sprinkle more shredded cheese on top. Bake the chicken zucchini casserole until the cheese on top is melted. If you like it browned more (highly recommend!), place under the broiler.

My Recipe Tips

I’ve been making this chicken zucchini casserole since 2018, but I made some tweaks to the recipe recently to improve it. And I discovered some additional tips along the way:

• Browning and stovetop temp depends on your pan. I use cast iron and sometimes need to turn it down, but with nonstick you may need the heat even higher.
• Use lower heat if you don’t want your chicken to darken. I like mine golden, but you can choose medium heat if you like less browning.
• It’s important to cook down the zucchini and mushrooms enough and let all the liquid evaporate. If you don’t, the casserole will be watery. If the zucchini starts to brown too much, reduce heat to medium but continue cooking to get it tender. If it’s crisp, it will release water when you bake the chicken zucchini casserole.
• Drain the chicken and veggies if needed. Sometimes the veggies still release more moisture as they sit while I make the sauce. If this happens, drain them again before mixing in the sauce.
• Save time by multitasking. I cut the zucchini while the mushrooms and onions cook, then make the Gruyere cheese sauce while the oven preheats.
• Do not use a whisk to mix in the shredded cheese. The cheese will clump on the whisk. I’ve found that a wooden spoon works best for this.
• Salt the sauce to taste. I didn’t need additional salt in the sauce, but this will vary depending on the broth and cheese brands you use.

Storage & Meal Prep

• Store: Keep leftovers in an airtight container in the refrigerator for up to 3-4 days. The veggies do get more mushy, but the flavor is still great.
• Meal prep: This chicken and zucchini casserole does have several steps, but it’s a breeze if you prep ahead! You can either just do the chopping in advance, or assemble the whole thing and keep it in the fridge (for 1-2 days) until ready to bake.
• Reheat: Just pop it in the oven for 15-20 minutes at 350 degrees F. The microwave works for individual portions if you’re in a hurry.
• Freeze: The assembled casserole freezes well for up to 3 months. You can reheat it from frozen at 350 degrees F, but this takes a long time (at least 45 minutes), so I usually thaw it in the fridge overnight for quicker heating.

More Cheesy Casserole Recipes

If you’re a fan of easy, cheesy casseroles like this, you’ll love my others:

Chicken Bacon Ranch Casserole

Loaded Cauliflower Casserole

Pepperoni Pizza Casserole

Cheesy Broccoli Casserole

Tools I Use For This Recipe

• Casserole Dish – My favorite brand. This one is a little smaller than your standard baking dish, but it’s the perfect size for this recipe. You can use a larger one, but it will be less full.
• Cast Iron Skillet – You need a big skillet to fit all those veggies before they cook down! And I love my cast iron for the best browning and evaporating extra moisture.

Recipe Video

Ingredients

Tap underlined ingredients to see the ones I use.

• 1 lb Boneless skinless chicken breast (cut into 1-inch pieces) ▢
• 3/4 tsp Sea salt (divided into 1/2 tsp and 1/4 tsp) ▢
• 1/2 tsp Black pepper (divided) ▢
• 2 tbsp Olive oil (divided) ▢
• 8 oz Mushrooms (sliced) ▢
• 1/2 large Onion (diced) ▢
• 3 medium Zucchini (cut into half-moons) ▢
• 1/2 cup Heavy cream ▢
• 1/3 cup Chicken broth, reduced sodium ▢
• 6 oz Swiss Gruyere shredded cheese blend (or just one of the two types; divided) ▢
• 1/2 cup Sour cream ▢

Instructions

Tap on the times in the instructions to start a kitchen timer.

Cook The Chicken:

1. Place the chicken pieces in a large bowl and pat dry with paper towels. Season with 1/2 teaspoon of salt and 1/4 teaspoon of pepper.
2. Heat 1 tablespoon of olive oil in a 12-inch skillet over medium-high heat. Add the chicken pieces and sear for 5-6 minutes , turning every couple of minutes to brown all sides, until cooked through. Remove the chicken to a large bowl, cover to keep warm, and set aside.

Cook The Veggies:

1. Add the remaining 1 tablespoon of olive oil to the pan and reduce heat to medium. Add the mushrooms and onions. Cook for 7-10 minutes , until the mushrooms are soft and there is no liquid in the pan.
2. Increase heat to medium-high. Add the zucchini. Season the vegetables with the remaining 1/4 teaspoon of salt and 1/4 teaspoon of pepper. Saute, stirring occasionally, for about 10 minutes , uncovered, until the zucchini is soft and a little browned. Most (if not all) of the liquid should evaporate.
3. Drain the veggies if any liquid remains and transfer to the bowl with the chicken. Set aside.

Make The Sauce:

1. Preheat the oven to 400 degrees F (191 degrees C).
2. While the oven preheats, add cream and chicken broth to the same skillet. Scrape the bottom of the pan with a wooden spoon to release any browned bits. Turn on the heat to medium-high and bring to a boil, then simmer for about 5 minutes , until thick enough to thinly coat the back of a spoon.
3. Reduce heat to low. Stir 3 ounces of the shredded cheese into the pan, until melted.
4. Remove from heat. Stir in the sour cream. If needed, season the sauce with salt and pepper to taste.

Assemble & Bake:

1. If any additional liquid has formed in the bowl with the zucchini and chicken, drain it. Then, pour the sauce into the bowl with the chicken and veggies. Mix to combine.
2. Transfer the mixture to a 10×7-inch casserole dish . Sprinkle the remaining 3 ounces of shredded cheese on top.
3. Bake for about 10 minutes , until the cheese on top is melted. If desired, place under the broiler for 2-3 minutes to brown the cheese on top.

LAST STEP: Leave a rating to help other readers, or tag me @wholesomeyum on Instagram. I’d love to hear from you!

Maya’s Recipe Notes

Serving size: 1 cup

I provide nutrition facts as a courtesy. Have questions about calculations or why you got a different result? Please see my nutrition policy .

Add Your NotesYour Notes

© Copyright Maya Krampf for Wholesome Yum. Please DO NOT SCREENSHOT OR COPY/PASTE recipes to social media or websites. We’d LOVE for you to share a link with photo instead.

Chicken Zucchini Casserole

Gratitude Moment

I just got back from a trip to sunny San Diego and didn’t even realize how much I needed a “real” vacation until it hit me. I travel a lot, but it’s always go, go, go — and a lot of it is for work.

This time, a group of my girl friends all went together for a relaxing weekend. And unlike most of our family trips that are pretty planned out, we just did whatever we felt like last-minute. It was just what I needed — even if it meant coming back to a 12-hour recipe photo shoot the next day. 😉

I did bring back a “lovely” sunburn, because clearly I underestimated the California sun with my SPF. It was worth it.

Free Printable: Low Carb & Keto Food List

• Want The Keto Cheat Sheet Printable PDF System?
• The Basic Keto Meal Formula
• Understanding Macros
• Keto Food Swaps
• Keto Food List
• Electrolyte Basics
• Keto Diet Types
• Want The Keto Cheat Sheet Printable PDF System?
• Recipe Reviews

Even though I have a great guide to starting a keto diet , people often ask me for a quick keto cheat sheet they can use. That’s why I created this simple keto diet cheat sheet , so that you can have all the info you need handy. We’ll cover the basic keto formula for building meals, foods to eat and to avoid, delicious keto swaps for high-carb foods, electrolyte basics, and 4 ways to follow the keto lifestyle.

You can keep reading to view this info, or download my keto cheat sheet printable pdf to print out or save ad-free on any device (plus the pdf has more details!).

Want The Keto Cheat Sheet Printable PDF System?

Get all this information and MORE in convenient printer-friendly format – 13 cheat sheet pages you can take with you anywhere or keep in your kitchen, plus 4 recipe cookbooks! Includes:

1. Keto food list (230+ foods) – Super detailed & color-coded, with net carb counts, so you’ll know exactly what to eat.
2. Foods to avoid on keto – Detailed and specific list so that you know exactly what to watch out for.
3. Macros cheat sheet – Explains everything you need to know about macros to succeed on keto.
4. Keto food swaps (60+ foods) – Covers virtually every food you love, so you don’t have to miss out!
5. Keto meal formula – With specific food ideas, so it’s easy to mix-and-match.
6. Keto flu guide – Understand what it is and exactly how to avoid it.
7. Electrolyte cheat sheet – With whole food ideas + bonus keto tips.
8. Keto Diet Types – Summary of 4 ways to do keto, so you can choose what fits you best.
9. FOUR (4!) Keto Swaps Recipe EBooks – Dozens of recipes to replace bread, rice, potatoes, pasta, desserts, and other carbs you’d otherwise miss.

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The Basic Keto Meal Formula

Eating keto doesn’t have to be complicated! While there are plenty of delicious easy keto recipes to choose from, you don’t even have to cook from a recipe to get started.

Simply follow the keto cheat sheet formula of protein + veggie + fat for your meals.

Be sure to choose a moderate amount of protein, only low carb vegetables (mostly ones that grow above ground), and generous fat to attain an optimal macro ratio. That’s approximately 60-75% of calories from fat, 20-25% protein, and 5-10% from carbohydrates. The table below will give you ideas for what to choose.

Understanding Macros

Macros are macronutrients for short. They include fat, protein, and carbohydrates.

You can calculate your own macros using the macro calculator , but the macro keto cheat sheet below will explain how to look at macros when following a keto lifestyle.

Carbs Are A Limit.

Keeping carbs low is what gets you into ketosis and keeps you there. Ketosis means that you’re using fat as your primary energy source instead of sugar, and requires keeping carbs very low.

A good starting point is 20-25 grams net carbs per day, but you can experiment after a few weeks to see if your body stays in ketosis at higher levels. People who are very active may be able to do more and stay in ketosis, up to around 50 grams per day.

“Carbs are a limit” means that you set a limit for how many carbs to eat per day and don’t exceed it. You don’t have to hit that limit, so if you’re under that’s okay, just don’t go over. Ideally most of your carbs would come from low carb vegetables, and if you’re eating enough veggies, you’ll usually get close to the limit naturally.

A common misconception is that reaching ketosis requires a certain macro ratio, but it’s really only restricting your carb intake that gets you there [ * ]. In the absence of sufficient carbs to use as energy, the body will switch to using fat as fuel. This is called the metabolic state of ketosis.

Protein Is A Goal.

Protein is made up of amino acids, the building blocks of all our cells. It’s a crucial for keeping our muscles strong and for many cellular functions [ * ].

“Protein is a goal” means that you always want to eat enough protein to reach the goal each day, but not exceed it too much. You want enough for your needs, but excess protein can trigger gluconeogenesis, which is protein being converted to sugar [ * ] and can kick you out of ketosis.

Fat Is A Lever.

Fat is the primary macronutrient in a keto lifestyle, because being in ketosis means that fat is your primary fuel source. Fat as a fuel source will come from your food, and if you are losing weight, from your body.

A big advantage of a keto lifestyle is the high fat intake. It keeps you full and satisfied, making it easier to stick to, and using it as the primary fuel source makes it easier on your body to burn body fat, with a lower chance of breaking down your muscle (provided you get enough protein).

Aside from reaching your protein goal and limiting your carbs, the remainder of your calories on a keto diet comes from fat.

Don’t fear fat – it’s your main energy source on keto, and getting enough of it trains your body to use fat for fuel instead of sugar. That means that as long as you are not overdoing your overall calorie intake, you’ll efficiently burn your body fat for fuel as well.

“Fat is a lever” means that you can increase or decrease your fat intake depending on your goals and hunger levels. Increase it (along with exercise) to gain muscle, or decrease it to lose weight.

Keto Food Swaps

One of my favorite challenges is creating recipes, or just discovering, keto food swaps. These are delicious keto replacements for traditionally high-carb or high-sugar foods.

So, I created this keto diet cheat sheet with all the swaps in one place! I also have more keto food swaps in my Easy Keto Cookbook .

Keto Swaps For Breakfast

Keto Swaps For Bread

Keto Swaps For Meals & Side Dishes

Keto Swaps For Snacks & Sauces

Keto Swaps For Cooking & Baking

Keto Swaps For Drinks

If you’re looking specifically for keto alcohol options, browse the full keto alcohol guide .

Keto Food List

When looking for a keto cheat sheet printable, the most-requested information is a keto food list.

The great thing is that keto doesn’t have to feel restrictive. It’s incredibly satisfying and there’s such a wide variety of foods you can eat!

Foods To Eat On Keto

• Leafy greens – Such as spinach, chard, and lettuce.
• Above-ground veggies – Such as peppers, zucchini, and cauliflower.
• Full-fat cream & cheese – Such as heavy cream, sour cream, and full-fat hard cheeses.
• Natural meats – Such as beef, lamb, and pork.
• Berries – Such as raspberries, blackberries, and strawberries.
• Avocados
• Unsweetened nut milks – Such as almond milk and coconut milk.
• Almond flour and coconut flour
• Eggs
• Healthy fats – Such as coconut oil, avocado oil, olive oil and butter.

Foods To Avoid On Keto

• White flour & sugar
• Rice & grains – Such as barley, wheat, and corn.
• Milk & yogurt – Such as fruit on the bottom yogurt, sweetened Greek yogurt, and all milk.
• Cereal
• Processed food – Such as granola bars, candy
• Most fruit – Such as apples, bananas, and grapes
• Hydrogenated fats – Such as vegetable oil, soybean oil, and margarine
• Sweetened beverages & condiments – Such as soda, ketchup, and sweet dressings
• Starchy veggies – Such as peas, carrots, and beets.
• Potatoes – Such as sweet potatoes and white potatoes.

That’s the short keto diet cheat sheet version of all the keto food categories, but I recommend downloading the full Keto Cheat Sheet System. It includes a super detailed printable keto food list with over 100 items, including 2 color-coded pages with net carb counts, along with 6 more pages of keto cheat sheets:

Get The Keto Cheat Sheet System PDF (Only $37)

Electrolyte Basics

Getting enough electrolytes is crucial for anyone, but especially so on a keto diet. The reason is that ketosis has a diuretic effect, which increases excretion of water and electrolytes, especially sodium [ * ]. This is often the cause of the keto flu.

For more details on electrolytes and avoiding keto flu, check out the full keto flu guide here .

The important thing to know about electrolytes is that replenishing them will keep keto flu away and keep your body functioning well. I always recommend an electrolyte drink and whole food sources of anything your body needs before resorting to supplements, so I made a list of what to eat to get each of the 3 major electrolytes – sodium, magnesium and potassium.

Here’s your keto diet cheat sheet for getting electrolytes from food:

Keto Diet Types

People follow a keto lifestyle for different reasons. Some do it just to lose weight, others are after better overall health, increased energy, and reduced inflammation.

Strictly speaking, the defining factor of a keto diet is the metabolic state of ketosis, which is achieved by restricting carbs. However, many people (myself included) also reduce or eliminate processed, inflammatory, or low-nutrient foods.

Below is your keto cheat sheet summary of the different ways that people follow keto. You choose what works best for your goals and lifestyle!

• Strict Keto – Up to 20-30g net carbs daily, count all calories and macros, and eat clean, unprocessed foods.
• Lazy Keto – Up to 20-30g net carbs daily, and track only net carbs OR eat keto foods without tracking.
• Dirty Keto – Up to 20-30g net carbs daily, with “if it fits your macros” approach including processed foods.
• Low Carb – Up to 50-100g net carbs daily, less strict.

For a more detailed listing of these different types of keto with pros and cons, grab the Easy Keto Cheat Sheet Printable PDF below!

Want The Keto Cheat Sheet Printable PDF System?

Get all this information and MORE in convenient printer-friendly format – 13 cheat sheet pages you can take with you anywhere or keep in your kitchen, plus 4 recipe cookbooks! Includes:

1. Keto food list (230+ foods) – Super detailed & color-coded, with net carb counts, so you’ll know exactly what to eat.
2. Foods to avoid on keto – Detailed and specific list so that you know exactly what to watch out for.
3. Macros cheat sheet – Explains everything you need to know about macros to succeed on keto.
4. Keto food swaps (60+ swaps) – Covers virtually every food you love, so you don’t have to miss out!
5. Keto meal formula – With specific food ideas, so it’s easy to mix-and-match.
6. Keto flu guide – Understand what it is and exactly how to avoid it.
7. Electrolyte cheat sheet – With whole food ideas + bonus keto tips.
8. Keto Diet Types – Summary of 4 ways to do keto, so you can choose what fits you best.
9. FOUR (4!) Keto Swaps Recipe EBooks – Dozens of recipes to replace bread, rice, potatoes, pasta, desserts, and other carbs you’d otherwise miss.

Get The Printable Keto Cheat Sheet System (75 pages, Only $37!)

Chicken Zucchini Casserole

This chicken zucchini casserole has a rich cheese sauce, plus more melty cheese on top! My easy cooking method keeps it from getting watery.

Scan this QR code with your phone’s camera for the full recipe, including tips, step-by-step photos, and storage, or to save it to your account. You can also find it at: https://www.wholesomeyum.com/chicken-zucchini-casserole/

Ingredients

• 1 lb Boneless skinless chicken breast (cut into 1-inch pieces)
• 3/4 tsp Sea salt (divided into 1/2 tsp and 1/4 tsp)
• 1/2 tsp Black pepper (divided)
• 2 tbsp Olive oil (divided)
• 8 oz Mushrooms (sliced)
• 1/2 large Onion (diced)
• 3 medium Zucchini (cut into half-moons)
• 1/2 cup Heavy cream
• 1/3 cup Chicken broth, reduced sodium
• 6 oz Swiss Gruyere shredded cheese blend (or just one of the two types; divided)
• 1/2 cup Sour cream

Instructions

Cook The Chicken:

1. Place the chicken pieces in a large bowl and pat dry with paper towels. Season with 1/2 teaspoon of salt and 1/4 teaspoon of pepper.
2. Heat 1 tablespoon of olive oil in a 12-inch skillet over medium-high heat. Add the chicken pieces and sear for 5-6 minutes , turning every couple of minutes to brown all sides, until cooked through. Remove the chicken to a large bowl, cover to keep warm, and set aside.

Cook The Veggies:

1. Add the remaining 1 tablespoon of olive oil to the pan and reduce heat to medium. Add the mushrooms and onions. Cook for 7-10 minutes , until the mushrooms are soft and there is no liquid in the pan.
2. Increase heat to medium-high. Add the zucchini. Season the vegetables with the remaining 1/4 teaspoon of salt and 1/4 teaspoon of pepper. Saute, stirring occasionally, for about 10 minutes , uncovered, until the zucchini is soft and a little browned. Most (if not all) of the liquid should evaporate.
3. Drain the veggies if any liquid remains and transfer to the bowl with the chicken. Set aside.

Make The Sauce:

1. Preheat the oven to 400 degrees F (191 degrees C).
2. While the oven preheats, add cream and chicken broth to the same skillet. Scrape the bottom of the pan with a wooden spoon to release any browned bits. Turn on the heat to medium-high and bring to a boil, then simmer for about 5 minutes , until thick enough to thinly coat the back of a spoon.
3. Reduce heat to low. Stir 3 ounces of the shredded cheese into the pan, until melted.
4. Remove from heat. Stir in the sour cream. If needed, season the sauce with salt and pepper to taste.

Assemble & Bake:

1. If any additional liquid has formed in the bowl with the zucchini and chicken, drain it. Then, pour the sauce into the bowl with the chicken and veggies. Mix to combine.
2. Transfer the mixture to a 10x7-inch casserole dish . Sprinkle the remaining 3 ounces of shredded cheese on top.
3. Bake for about 10 minutes , until the cheese on top is melted. If desired, place under the broiler for 2-3 minutes to brown the cheese on top.

Maya’s Recipe Notes

Serving size: 1 cup

I provide nutrition facts as a courtesy. Have questions about calculations or why you got a different result? Please see my nutrition policy .

© Copyright Maya Krampf for Wholesome Yum. Please DO NOT SCREENSHOT OR COPY/PASTE recipes to social media or websites. We’d LOVE for you to share a link with photo instead. :)

FREE 5-Ingredient Recipe EBook

• Why You Need My Chicken Zucchini Casserole
• Ingredients & Substitutions
• How To Make Chicken Zucchini Casserole
• My Recipe Tips
• Storage & Meal Prep
• More Cheesy Casserole Recipes
• Tools I Use For This Recipe
• Chicken Zucchini Casserole Recipe card
• Gratitude Moment
• Recipe Reviews

Casseroles are some of my favorite healthy dinners because you only need to make one dish—no need for a separate main and side. And even though my chicken zucchini casserole has some pre-cooking steps (as casseroles often do), I still love the simplicity of this one-recipe meal. And the perfect excuse to use more zucchini . And the cheesy gruyere sauce that totally feels like comfort food. Make it with me and make the most of zucchini season!

Why You Need My Chicken Zucchini Casserole

• Luscious gruyere cheese sauce – The sauce is what sets this one apart from your run-of-the-mill chicken casserole. You’ll love the rich, cheesy, and bold flavor! It doesn’t look like a lot of sauce because the veggies absorb some of it, but make no mistake, you can taste it in every bite!
• Never watery – If you’ve made my standalone zucchini casserole before, you know I won’t settle for anything less. This time I use a different method, but the texture is just as important. Don’t miss my tips below!
• Easy, healthy meal – The steps are straightforward, the ingredients are fresh and simple, and it’s packed with protein and veggies. Plus, it’s meal prep friendly, so you can even enjoy my chicken zucchini casserole on busy weeknights. You don’t need any sides, but you could start with a soup or salad , or finish off your meal with my summery cherry crisp .

Ingredients & Substitutions

Here I explain the best ingredients for my chicken zucchini casserole recipe, what each one does, and substitution options. For measurements, see the recipe card .

Main Ingredients:

• Chicken – I usually use boneless skinless chicken breast, but boneless chicken thighs also work. Cut the chicken into 1-inch pieces. Or if you’ve got leftover chicken bites , Instant Pot shredded chicken , or even a rotisserie chicken, feel free to use those — and save time by skipping the pan searing step.
• Vegetables – I used sautéed mushrooms, onions, and of course, zucchini. Yellow squash actually works just as well instead of zucchini. You can also toss in bell peppers or broccoli if you like.
• Olive Oil – For searing the chicken and sauteing the veggies. Avocado oil works just as well.
• Sea Salt & Black Pepper

VARIATION: Add garlic for more flavor!

I didn’t add garlic in my casserole, but feel free to add 2-4 cloves of minced garlic—just sauté them with the onions and mushrooms.

Cheese Sauce:

• Shredded Cheese – The star of my chicken zucchini casserole is the Swiss Gruyere cheese blend! I love the nutty, slightly sweet flavor. If you can’t find a blend, you can just shred both cheeses yourself. If you prefer a milder flavor, swap in a combo of parmesan and mozzarella cheese instead.
• Heavy Cream – This makes the sauce rich and creamy. If you’re looking for a lighter option, you can substitute with half-and-half or whole milk, but the sauce will be less thick.
• Chicken Broth – You can use my homemade chicken broth or a reduced-sodium store-bought version . If all you have is regular, I recommend using less salt on your chicken and veggies.
• Sour Cream – For more richness and tang. Greek yogurt works well as a substitute. Cream cheese can also work, but you might need a splash of extra cream, since it’s thicker.

How To Make Chicken Zucchini Casserole

I have step-by-step photos here to help you visualize the recipe. For full instructions with amounts and temperatures, see the recipe card .

1. Season & dry the chicken. Place the chicken pieces in a large bowl and pat dry with paper towels. Season with salt and pepper.
2. Cook the chicken. Heat olive oil in a large skillet over medium-high. Add the chicken pieces and sear, turning to brown all sides until cooked through. Transfer to a bowl and cover to keep warm.

1. Sauté the mushrooms & onions. Add more olive oil to the pan, reduce the heat, and add the mushrooms and onions. Cook until the mushrooms are soft and there is no liquid in the pan.
2. Cook the zucchini. Turn the heat to medium-high again, add the zucchini, and season with salt and pepper. Sauté until soft and slightly browned, then drain any remaining liquid. Transfer to the bowl with the chicken and set aside.

1. Make the sauce. While your oven preheats, add the heavy cream and chicken broth to the same skillet. Scrape up any browned bits with a wooden spoon. Simmer for about 5 minutes, until the sauce coats the back of a spoon. Then, stir in shredded cheese, until melted.

1. Assemble & bake. Pour the sauce into the bowl with the chicken and veggies. Mix to combine, then transfer the mixture to a small baking dish ( I use this one and it’s the perfect size). Sprinkle more shredded cheese on top. Bake the chicken zucchini casserole until the cheese on top is melted. If you like it browned more (highly recommend!), place under the broiler.

My Recipe Tips

I’ve been making this chicken zucchini casserole since 2018, but I made some tweaks to the recipe recently to improve it. And I discovered some additional tips along the way:

• Browning and stovetop temp depends on your pan. I use cast iron and sometimes need to turn it down, but with nonstick you may need the heat even higher.
• Use lower heat if you don’t want your chicken to darken. I like mine golden, but you can choose medium heat if you like less browning.
• It’s important to cook down the zucchini and mushrooms enough and let all the liquid evaporate. If you don’t, the casserole will be watery. If the zucchini starts to brown too much, reduce heat to medium but continue cooking to get it tender. If it’s crisp, it will release water when you bake the chicken zucchini casserole.
• Drain the chicken and veggies if needed. Sometimes the veggies still release more moisture as they sit while I make the sauce. If this happens, drain them again before mixing in the sauce.
• Save time by multitasking. I cut the zucchini while the mushrooms and onions cook, then make the Gruyere cheese sauce while the oven preheats.
• Do not use a whisk to mix in the shredded cheese. The cheese will clump on the whisk. I’ve found that a wooden spoon works best for this.
• Salt the sauce to taste. I didn’t need additional salt in the sauce, but this will vary depending on the broth and cheese brands you use.

Storage & Meal Prep

• Store: Keep leftovers in an airtight container in the refrigerator for up to 3-4 days. The veggies do get more mushy, but the flavor is still great.
• Meal prep: This chicken and zucchini casserole does have several steps, but it’s a breeze if you prep ahead! You can either just do the chopping in advance, or assemble the whole thing and keep it in the fridge (for 1-2 days) until ready to bake.
• Reheat: Just pop it in the oven for 15-20 minutes at 350 degrees F. The microwave works for individual portions if you’re in a hurry.
• Freeze: The assembled casserole freezes well for up to 3 months. You can reheat it from frozen at 350 degrees F, but this takes a long time (at least 45 minutes), so I usually thaw it in the fridge overnight for quicker heating.

More Cheesy Casserole Recipes

If you’re a fan of easy, cheesy casseroles like this, you’ll love my others:

Chicken Bacon Ranch Casserole

Loaded Cauliflower Casserole

Pepperoni Pizza Casserole

Cheesy Broccoli Casserole

Tools I Use For This Recipe

• Casserole Dish – My favorite brand. This one is a little smaller than your standard baking dish, but it’s the perfect size for this recipe. You can use a larger one, but it will be less full.
• Cast Iron Skillet – You need a big skillet to fit all those veggies before they cook down! And I love my cast iron for the best browning and evaporating extra moisture.

Recipe Video

Ingredients

Tap underlined ingredients to see the ones I use.

• 1 lb Boneless skinless chicken breast (cut into 1-inch pieces) ▢
• 3/4 tsp Sea salt (divided into 1/2 tsp and 1/4 tsp) ▢
• 1/2 tsp Black pepper (divided) ▢
• 2 tbsp Olive oil (divided) ▢
• 8 oz Mushrooms (sliced) ▢
• 1/2 large Onion (diced) ▢
• 3 medium Zucchini (cut into half-moons) ▢
• 1/2 cup Heavy cream ▢
• 1/3 cup Chicken broth, reduced sodium ▢
• 6 oz Swiss Gruyere shredded cheese blend (or just one of the two types; divided) ▢
• 1/2 cup Sour cream ▢

Instructions

Tap on the times in the instructions to start a kitchen timer.

Cook The Chicken:

1. Place the chicken pieces in a large bowl and pat dry with paper towels. Season with 1/2 teaspoon of salt and 1/4 teaspoon of pepper.
2. Heat 1 tablespoon of olive oil in a 12-inch skillet over medium-high heat. Add the chicken pieces and sear for 5-6 minutes , turning every couple of minutes to brown all sides, until cooked through. Remove the chicken to a large bowl, cover to keep warm, and set aside.

Cook The Veggies:

1. Add the remaining 1 tablespoon of olive oil to the pan and reduce heat to medium. Add the mushrooms and onions. Cook for 7-10 minutes , until the mushrooms are soft and there is no liquid in the pan.
2. Increase heat to medium-high. Add the zucchini. Season the vegetables with the remaining 1/4 teaspoon of salt and 1/4 teaspoon of pepper. Saute, stirring occasionally, for about 10 minutes , uncovered, until the zucchini is soft and a little browned. Most (if not all) of the liquid should evaporate.
3. Drain the veggies if any liquid remains and transfer to the bowl with the chicken. Set aside.

Make The Sauce:

1. Preheat the oven to 400 degrees F (191 degrees C).
2. While the oven preheats, add cream and chicken broth to the same skillet. Scrape the bottom of the pan with a wooden spoon to release any browned bits. Turn on the heat to medium-high and bring to a boil, then simmer for about 5 minutes , until thick enough to thinly coat the back of a spoon.
3. Reduce heat to low. Stir 3 ounces of the shredded cheese into the pan, until melted.
4. Remove from heat. Stir in the sour cream. If needed, season the sauce with salt and pepper to taste.

Assemble & Bake:

1. If any additional liquid has formed in the bowl with the zucchini and chicken, drain it. Then, pour the sauce into the bowl with the chicken and veggies. Mix to combine.
2. Transfer the mixture to a 10×7-inch casserole dish . Sprinkle the remaining 3 ounces of shredded cheese on top.
3. Bake for about 10 minutes , until the cheese on top is melted. If desired, place under the broiler for 2-3 minutes to brown the cheese on top.

LAST STEP: Leave a rating to help other readers, or tag me @wholesomeyum on Instagram. I’d love to hear from you!

Maya’s Recipe Notes

Serving size: 1 cup

I provide nutrition facts as a courtesy. Have questions about calculations or why you got a different result? Please see my nutrition policy .

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Chicken Zucchini Casserole

Gratitude Moment

I just got back from a trip to sunny San Diego and didn’t even realize how much I needed a “real” vacation until it hit me. I travel a lot, but it’s always go, go, go — and a lot of it is for work.

This time, a group of my girl friends all went together for a relaxing weekend. And unlike most of our family trips that are pretty planned out, we just did whatever we felt like last-minute. It was just what I needed — even if it meant coming back to a 12-hour recipe photo shoot the next day. 😉

I did bring back a “lovely” sunburn, because clearly I underestimated the California sun with my SPF. It was worth it.