Name: Cheesy Zucchini, Summer Squash, and Corn Casserole
Prep time: 15 min
Cook time: 45 min
Total time: 60 min
Ingredients: 2 small zucchini; 2 small summer squash; 1 large onion; 2 garlic cloves; 4 tablespoons butter; 2 cups sweet corn; 2 cups Cheddar cheese; ½ cup sour cream; ½ cup mayonnaise; 2 eggs; 1 cup grated parmesan; 1½ cup breadcrumbs; 1 teaspoon salt; 2 teaspoons pepper; 2 tablespoons buttery herb and galic seasoning

Jump to Recipe Print Recipe

There are never enough ways to make zucchini in the summer. One of the ultimate zucchini casseroles I have made is this cheesy zucchini, squash, and corn casserole with a creamy cheesy inside and crisp breadcrumb topping. Can anything beat Zucchini, Squash, Corn, Onion, garlic, cheddar cheese with breadcrumbs and parmesan cheese? You will definitely want to try this old-fashioned feeling zucchini casserole.

One of the ultimate zucchini casseroles I have made is this cheesy zucchini, squash, and corn casserole with a creamy cheesy inside and crisp breadcrumb topping.

If you like creamy, cheesy goodness, this vegetable casserole is for you. I am a sucker for anything with a breadcrumb or in this case, crushed crouton topping like this smoked mac and cheese recipe. This casserole is a bit like a squash au gratin casserole. Bonus that it also adds the other summer favorite, corn to the casserole. You an also find the yummy corn pudding casserole on the blog.

Table of Contents

Cheesy Zucchini Squash Casserole Ingredients

Use a clear shot of the ingredients for this recipe, prepped, and labeled if necessary. Insert the ingredients into the list below, omitting quantities.

Zucchini
Summer Squash
Corn
Onion
Garlic
Cheddar cheese
sour cream
mayonnaise
eggs
breadcrumbs
parmesan cheese
Butter
Garlic and Herb Seasoning

See the recipe card for quantities.

How to Make Zucchini, Squash, and Corn Casserole

This casserole is a bit of a process to make, but it is so worth it. Nothing is hard to do, but it isn’t just thrown together in a few minutes. Here is what you need to do to make this cheesy vegetable casserole.

Thinly slice the squash, both zucchini and yellow summer squash. Add to a skillet that has melted butter in it with the onions and garlic.

Stir together the mayonnaise, sour cream, cheddar cheese, eggs, and seasonings. Then stir in the squash saute with the corn, breadcrumbs, and parmesan cheese.

Transfer to a greased 13 X 9 casserole dish. Melt remaining butter and mix with breadcrumbs and parmesan. Spread over the casserole.

Place into oven at 350 degrees Fahrenheit and bake uncovered for 45 minutes.

Remove the zucchini, squash, and corn casserole from the oven and let it cool for a few minutes before serving. It is divine. Definitely a great way to have a creamy way of eating squash.

Substitutions

If you know how to make the recipe fit a certain diet, let the reader know here. Don’t fake it – only provide guidance on topics you have actual experience with.

Breadcrumbs – don’t have breadcrumbs on hand, toss some croutons in the blender and crush them up. You are good to go with breadcrumbs. Want fewer carbs or gluten-free versions try some almond flour.
Cheddar Cheese – Honestly, cheddar cheese isn’t a must. Colby-Jack, white cheddar, or Monterey jack cheese is a great option too.
Sour Cream – a great substitute for sour cream is plain greek yogurt. It might be a bit tangier than sour cream but an easy alternative for sour cream.

If you prefer to not have breadcrumb topped casserole, here is a great cheesy zucchini and squash casserole. Looking for one without cream or cheese? Then this healthy zucchini casserole might be one for you to try.

Squash Casserole Variations

Change up the flavors in this recipe or adjust to diet requirements with these ideas on how to bring spice, low-carb, and gluten-free options into the zucchini casserole recipe.

Spicy – add chili pepper flakes to the sauce and some poblano peppers or jalapeno peppers to the skillet when you are sauteing the squash.
Lower Carb – Leave out the corn and substitute the almond flour for the breadcrumbs. You can also add mushrooms to offer another dimension.
Gluten-Free – for the gluten-free version, almond flour substituted for the breadcrumbs

Looking for a non-cream-based version of this recipe check out the zucchini, corn, and mushroom skillet. There is also a version of this zucchini and corn casserole with ritz crackers on top that looks amazing too.

Storing Leftover Cheesy Zucchini Casserole Leftovers

Refrigerating: Store leftover zucchini, squash, and corn casserole in the refrigerator covered tightly with foil or plastic wrap. It should keep for up to three days.
Freezing: Not recommended. The cream-based sauce doesn’t thaw very well after being frozen.

Great Vegetable Side Dish Recipes

Shaved Brussels Sprouts with Bacon

Shaved Brussels Sprouts with bacon sautéed on the stovetop and finished off with some lemon juice is the fastest way to make Brussels sprouts side dishes.

Get the Recipe Now

Instant Pot Butternut Squash Risotto

Instant Pot butternut squash risotto is a creamy risotto recipe has a hint of sweetness but savory in flavor from the onion, garlic, and sage and is made in under 20 minutes.

Get the Recipe

Zucchini and Summer Squash Recipe

Skillet zucchini and summer squash recipe with corn and mushrooms is a quick sauteed squash recipe that comes together with lots of flavors thanks to onions, garlic, and fresh herbs.

Get the Recipe

Cheesy Zucchini, Summer Squash, and Corn Casserole

One of the ultimate zucchini casseroles I have made is this cheesy zucchini, squash, and corn casserole with a creamy cheesy inside and crisp breadcrumb topping.

No ratings yet

Print Rate

Course: Side Dish, Vegetable

Keyword: Casserole, Cast Iron Skillet recipe, cheese, creamy, sauté, yellow squash

Prep Time: 15

Cook Time: 45

Total Time: 1

Servings: servings

Calories: 332kcal

Author: Leah @ Beyer Beware

Equipment

1 cast-iron skillet
1 13 X 9 Casserole Pan

Ingredients

2 small zucchini
2 small summer squash
1 large onion
2 garlic cloves
4 tablespoons butter
2 cups sweet corn
2 cups Cheddar cheese
½ cup sour cream
½ cup mayonnaise
2 eggs
1 cup grated parmesan
1½ cup breadcrumbs
1 teaspoon salt
2 teaspoons pepper
2 tablespoons buttery herb and galic seasoning

Get Recipe Ingredients

Instructions

Thinly slice the squash, both zucchini and yellow summer squash. Add to a skillet that has 2 tablespoons melted butter in it with the onions and garlic.
Stir together the mayonnaise, sour cream, cheddar cheese, eggs, and seasonings. Then stir in the squash saute with the corn, breadcrumbs, and parmesan cheese.
Transfer to a greased 13 X 9 casserole dish. Melt remaining butter and mix with breadcrumbs and parmesan. Spread over the casserole.
Place into oven at 350 degrees Fahrenheit and bake uncovered for 45 minutes.
Remove the zucchini, squash, and corn casserole from the oven and let it cool for a few minutes before serving.

Follow Me

Leah

A working mom of two very active teenagers. My husband and I gave up running the 80-cow dairy farm that also included a couple of hundred acres of corn and soybeans to both work to support the agricultural industry. We still have about 20 head of dairy heifers and cows to help my kids appreciate the effort it takes to raise livestock. I consider myself a foodie as I love cooking and experimenting with recipes. My family just wishes I would make the same thing twice. Find my other blog, FarmWifeDrinks.com for all things cocktails.