Cheesy Zucchini Corn Casserole

Ingredients

For the Vegetables

• 2 pounds zucchini, quartered lengthwise and sliced
• 1 teaspoon kosher salt, divided
• 2 tablespoons unsalted butter
• 1 small yellow onion, diced
• 2 garlic cloves, minced
• 3 cups corn kernels, fresh or thawed and dried

For the Filling

• 2 large eggs
• 1 cup sour cream
• 1 cup shredded sharp cheddar cheese
• 1/2 teaspoon black pepper
• 1/2 teaspoon dried thyme

For the Topping

• 1 cup panko breadcrumbs
• 2 tablespoons melted butter
• 1/4 cup grated Parmesan cheese
• 2 tablespoons chopped fresh parsley

Substitutions

• Yellow summer squash can replace half or all of the zucchini.
• Plain Greek yogurt can replace sour cream but gives a tangier filling.
• Monterey Jack can replace cheddar for a milder, stretchier result.
• Gluten-free panko works, though browning may be slightly lighter.

Instructions

Step 3: Sauté the Vegetables

Melt 2 tablespoons butter in a skillet. Cook onion 4 minutes, add zucchini and corn, and sauté 6 to 7 minutes until the zucchini begins to soften and excess moisture evaporates. Add garlic for 30 seconds.

Step 4: Mix the Filling

Whisk eggs, sour cream, cheddar, remaining salt, black pepper, and thyme in a large bowl.

Step 6: Add the Crumb Topping

Mix panko, melted butter, Parmesan, and parsley. Scatter evenly over the casserole without pressing it down.

Step 7: Bake Until Set

Bake 30 to 35 minutes until the edges bubble, the center is set, and the crumb topping is golden. The egg-based center should reach 160°F.

Step 8: Rest and Serve

Rest 10 minutes before spooning so the creamy filling holds its shape.

How to Store Leftovers

Refrigerate the casserole within 2 hours, covered, for up to 4 days. Keep any extra fresh parsley separate until serving.

Freeze cooled portions for up to 2 months, but expect the zucchini to soften slightly after thawing. Thaw overnight before reheating.

How to Reheat

Reheat uncovered in a 350°F oven for 15 to 20 minutes until 165°F, adding 2 minutes under the broiler if the topping needs re-crisping. Microwaving works but softens the crumbs.

What to Serve With It

• roasted chicken
• grilled salmon
• tomato cucumber salad
• crusty bread
• lemony mixed greens

Common Mistakes to Avoid

• Skipping the zucchini salting and drying step.
• Adding frozen corn while still icy.
• Overcooking the vegetables before baking.
• Pressing the breadcrumbs into the wet filling.

Nutrition Information

Nutrition is an estimate and can vary with brands, portion size, ripeness, and substitutions.

Frequently Asked Questions