Name: Zucchini Squash & Corn Casserole
Prep time: 15 min
Cook time: 30 min
Total time: 45 min
Cuisine: American
Ingredients: 2 medium zucchinis, sliced; 2 medium yellow squash, sliced; 1 cup corn kernels (fresh or frozen); 1/2 cup sour cream; 1/2 cup mayonnaise; 1 cup shredded cheddar cheese; 1/4 cup grated Parmesan cheese; 1/4 cup breadcrumbs (optional, for topping); 1 tablespoon olive oil; 1/2 teaspoon garlic powder; 1/2 teaspoon onion powder; Salt and pepper, to taste; Fresh parsley, chopped, for garnish

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Why You’ll Love This Recipe

I love how this casserole turns simple vegetables into something truly satisfying. It’s quick to prep, bakes beautifully, and pairs well with almost any meal. The cheesy, creamy base brings out the natural sweetness of the corn and the soft bite of zucchini and squash. Whether I’m hosting friends or just need a comforting dish for the family, this one never disappoints.

ingredients

(Here’s a tip: Check out the full list of ingredients and measurements in the recipe card below.)

2 medium zucchinis, sliced
2 medium yellow squash, sliced
1 cup corn kernels (fresh or frozen)
1/2 cup sour cream
1/2 cup mayonnaise
1 cup shredded cheddar cheese
1/4 cup grated Parmesan cheese
1/4 cup breadcrumbs (optional for topping)
1 tablespoon olive oil
1/2 teaspoon garlic powder
1/2 teaspoon onion powder
Salt and pepper to taste
Fresh parsley, chopped for garnish

directions

I preheat the oven to 375°F (190°C) and grease a 9×9-inch baking dish with olive oil or cooking spray.
In a large skillet, I heat olive oil over medium heat. Then I add the sliced zucchini and squash, cooking them for about 4–5 minutes until they start to soften.
I stir in the corn and cook everything together for another 2–3 minutes. Then I take it off the heat and set it aside.
In a medium bowl, I mix the sour cream, mayonnaise, cheddar cheese, Parmesan cheese, garlic powder, onion powder, salt, and pepper until smooth.
I gently fold in the cooked vegetables until everything is evenly coated.
I pour the mixture into the prepared baking dish and smooth it out evenly.
If I’m using breadcrumbs, I sprinkle them on top for a crispy finish.
I bake the casserole for 25–30 minutes until the top is golden and the edges are bubbling.
Just before serving, I garnish it with freshly chopped parsley for a touch of color and freshness.

Servings and timing

This casserole makes 6 servings.

Prep Time: 15 minutes
Cooking Time: 30 minutes
Total Time: 45 minutes
Calories: 290 kcal per serving

Variations

I sometimes like to add chopped red bell peppers or green onions for extra flavor and color. If I’m craving a little spice, I mix in a pinch of crushed red pepper flakes. For a different cheese profile, I swap in mozzarella or pepper jack. And when I want to keep it lighter, I use Greek yogurt instead of sour cream and reduce the mayonnaise.

storage/reheating

If I have leftovers, I store them in an airtight container in the fridge for up to 3 days. To reheat, I use the oven at 350°F (175°C) for about 10–15 minutes, or I microwave individual portions for 1–2 minutes until hot. I find the texture stays best with oven reheating.

FAQs

Can I make this casserole ahead of time?

Yes, I often prep it a day ahead and store it covered in the fridge. When I’m ready to bake, I just pop it into the oven as directed.

Can I freeze this casserole?

I usually don’t freeze it because the creamy ingredients can change texture. But if I need to, I freeze it before baking, tightly wrapped, and bake it from frozen with an added 10–15 minutes.

What can I use instead of mayonnaise?

I’ve tried replacing mayonnaise with Greek yogurt or more sour cream, and it works well if I’m looking for a lighter option.

Is it necessary to use breadcrumbs?

Not at all. I add them when I want a crunchy topping, but the casserole is just as good without them.

Can I add protein to this casserole?

Absolutely. I sometimes mix in cooked chicken or crumbled sausage to turn it into a full main dish.

Conclusion

This Zucchini Squash & Corn Casserole is one of those easy, flexible recipes I love coming back to. It’s packed with vegetables, rich in flavor, and always comes out of the oven looking and smelling amazing. Whether I’m serving it at a holiday table or just enjoying a weeknight meal, it’s pure comfort in every bite.