Easy Baked Cheesy Zucchini Casserole Recipe

This easy cheesy zucchini casserole is a family-favorite summer side dish made with Bisquick, fresh zucchini, herbs, and lots of cheese! It also works well as a light main dish or breakfast recipe.

My grandma used to make this dish every summer with her abundance of zucchini. Her original recipe used a full cup of oil (she used vegetable or canola oil). Over time, I have been able to cut the amount of oil in half (and started using olive oil) without compromising this delicious old-fashioned casserole!

Zucchini is low in calories but high in fiber and vitamins (like vitamin C and vitamin K) and minerals, making it a fantastic addition to your diet.

It’s also super versatile! Since zucchini takes on the flavors around it really well, it works in both sweet and savory dishes.

When it comes to sweet dishes, I love making my no-fail zucchini muffins and fudgy zucchini brownies. But when it comes to savory dishes, I like making my Vietnamese-inspired noodle bowl and this zucchini casserole.

This easy zucchini casserole (also called zucchini bake or zucchini pie) is a savory dish made with zucchini mixed with other ingredients such as onions, cheese, eggs, and herbs. All of that is baked in a biscuit mixture with a similar texture to a quiche.

I love making this because it’s a great recipe for adding more vegetables into my kids’ diet in a delicious way – they all love it!

Ingredients

• Garden zucchini
• Onion
• Mozzarella Cheese
• Garlic
• Parsley, finely chopped
• Salt and Black Pepper
• Biscuit Mix
• Eggs
• Olive oil
• Grated Parmesan Cheese

​NOTE: For more recipe details, please check out the handy printable recipe card at the bottom of this post!

How To Make Zucchini Casserole

Step 1 – Preheat Oven

Preheat oven to 375F. Grease a X 8″ x 13″ casserole dish with non-stick cooking spray and set aside.

Step 2 – Cut Up Veggies and Add Seasonings

Dice the zucchini, onion and mozzarella cheese into approximately the same sizes (1/4″ pieces) and place in a large bowl.

Stir to combine, then season with garlic, salt, pepper and parsley, stirring again to evenly distribute the seasoning. Set aside.

Step 3 – Add Biscuit Mix, Eggs, Oil

In a medium-sized bowl, combine the biscuit mix, eggs and oil. Whisk until completely combined.

Pour the biscuit mixture into the large bowl containing the zucchini mixture. Stir well to combine.

Step 4 – Add Cheese

Add 1/2 cup of the grated Parmesan cheese and stir to incorporate.

Step 5 – Top With Cheese and Bake

Pour the zucchini casserole mixture into the prepare casserole dish.

Top with the remaining 1/2 cup of grated Parmesan cheese.

Bake the zucchini casserole in the preheated oven for 45-50 minutes, until the cheese topping is golden brown, and an inserted toothpick comes out clean.

Healthy Zucchini Casserole Expert Notes and Tips

• The biscuit mix helps hold everything together and gives a biscuit-like coating around the zucchini.

• I have tested this recipe using both Bisquick and pancake mix, and both worked great!

• I recommend enjoying your zucchini casserole the day it is made.

• Grease your pan! Use your favorite cooking spray – I prefer using avocado oil spray.

• Cook this casserole completely through. It has eggs in it, and can be runny if they aren’t fully cooked.

• This zucchini casserole recipe is forgiving – if you use slightly more/less of any ingredient (zucchini, cheese, onion, seasonings, etc.), it’s ok!

Variations To Try

• Mix up the squash – I have tried making this with half fresh zucchini and half yellow squash – zucchini squash casserole comes out great!

• Herbs – No parsley? Swap out dried basil or dried oregano. You could also use fresh oregano or fresh basil.

• Onions – Use whatever onion you have: yellow onion, white onion, sweet onion, red onion, or even green onions!

• Add more veggies – If you love bell peppers, you could definitely add some diced bell peppers (any color!) to this delicious casserole.

• Cheese – Feel free to swap out the mozzarella cheese for cheddar or colby jack cheese! And if you really love cheese, add an extra 1/2 cup for extra cheesy goodness.

• Add heat – if you love a little spice in your food, you can add red pepper flakes
   to taste.

• Add protein – if you want to add some protein to this easy side dish, you can add some ground beef or chicken to make chicken zucchini casserole.

Make Gluten-Free Zucchini Casserole

It’s easy to make gluten-free by simply substituting a cup-for-cup gluten-free baking mix for the Bisquick. (Note that you can’t just sub almond flour or coconut flour; it needs to be a complete baking mix.

How To Serve Zucchini Casserole

This flavorful dish is the perfect side dish for so many meals! Try serving it with:

• BBQ Chicken Wings
• Homemade Chicken Salad Recipe With Grapes
• Baked Honey Mustard Chicken Thighs
• Air Fryer Greek Chicken Kabobs
• Homemade Crispy Baked Chicken Tenders
• Easy Bang Bang Salmon

Zucchini Casserole Storage Tips

Leftovers – If you have leftover zucchini casserole, store it in an airtight container in the fridge for up to 3 days.

Make it ahead of time – I wouldn’t recommend putting this casserole together ahead of time. However, if you want to save time, chop the zucchini and onion up to 1 day in advance and refrigerate them. Then, when you’re ready to bake the casserole, combine everything together and bake. 

Freezing Instructions – You can freeze the casserole after it’s been baked. First, cool completely, then cover it with plastic wrap, followed by a layer of aluminum foil. Freeze for up to 2 months.

To enjoy, thaw for 24 hours in the fridge. When you’re ready to enjoy it, uncover the casserole and reheat in the oven until hot all the way through. 

More Delicious Zucchini Recipes

If you love this casserole idea, you’ll also love these delicious recipes!

• Carrot Zucchini Bars
• Air Fryer Zucchini Sticks
• Zucchini Cookies With Cream Cheese Frosting
• Lemon Blueberry Zucchini Bread
• Lemon Zucchini Bread Recipe (+ Easy Glaze)
• Chocolate Chip Zucchini Bread

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