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.
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. This casserole is a bit like a squash au gratin casserole. Bonus that it also adds the other summer favorite, corn to the casserole.
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.
- Summer Squash
- Cheddar cheese
- sour cream
- parmesan cheese
- 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.
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
Cheesy Zucchini, Summer Squash, and Corn Casserole
- 1 cast-iron skillet
- 1 13 X 9 Casserole Pan
- 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
- 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.