Can I make zucchini casserole ahead of time?

Yes, you can assemble the casserole up to 1 day in advance. Cover it tightly and refrigerate before baking. When ready to cook, let it sit at room temperature for 20–30 minutes, then bake as directed. This makes it perfect for meal prep or holiday planning.

Can I freeze zucchini casserole?

You can freeze it after baking. Let the casserole cool completely, then wrap it well and freeze for up to 2 months. To reheat, thaw overnight in the fridge and bake at 350ºF until warmed through. Freezing before baking isn’t recommended, as raw zucchini can become mushy.

What’s a good substitute for Greek yogurt in this recipe?

Sour cream works perfectly as a 1:1 swap. For a lighter option, try whole-milk ricotta or even plain cottage cheese blended until smooth. Avoid low-fat versions, as they release more liquid and may affect texture.

Can I add meat or other veggies to this zuchini casserole?

Absolutely. Cooked ground turkey, shredded rotisserie chicken, or sautéed mushrooms all blend well. Just make sure any added ingredients are fully cooked and not too wet. Try folding in roasted red peppers or chopped spinach for extra color and flavor.

Zucchini Casserole Recipe: Ultimate Cheesy Favorite

Ingredients

Scale

Cooking spray

2 1/2 pounds zucchini (6 to 8 medium)

1 small yellow onion, finely chopped or grated

2 1/2 teaspoons kosher salt, divided

1 3/4 cups panko breadcrumbs, divided

2 1/2 ounces grated Parmesan cheese

3 large eggs

2/3 cup full-fat plain Greek yogurt or sour cream

2 teaspoons Dijon mustard

1 teaspoon garlic powder

1/2 teaspoon dried oregano

1/4 teaspoon black pepper

4 ounces shredded sharp cheddar cheese

2 tablespoons melted butter or olive oil

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Instructions

1. Preheat oven to 375ºF. Spray 9×13 baking dish with cooking spray.

2. Grate zucchini and place in colander with chopped onion and 2 tsp salt. Let sit 20 min.

3. Squeeze zucchini mixture to remove excess moisture.

4. In a large bowl, mix 1 1/4 cups panko, Parmesan, eggs, yogurt, mustard, garlic powder, oregano, 1/2 tsp salt, pepper.

5. Stir in drained zucchini and onion.

6. Spread mixture into baking dish evenly.

7. Top with shredded cheddar cheese.

8. In the same bowl, mix remaining 1/2 cup panko with melted butter. Sprinkle on top.

9. Bake 35–45 minutes until bubbly and golden brown.

Notes

You can prep the casserole up to a day ahead and bake when ready.

Leftovers keep well in the fridge for up to 3 days.

Sour cream can be used instead of Greek yogurt.

Author: Chef Saly
Prep Time: 25 minutes
Cook Time: 40 minutes
Category: Side Dish
Method: Baking
Cuisine: American
Diet: Vegetarian

Nutrition

Serving Size: 1 slice
Calories: 210
Sugar: 4g
Sodium: 540mg
Fat: 13g
Saturated Fat: 6g
Unsaturated Fat: 6g
Trans Fat: 0g
Carbohydrates: 15g
Fiber: 2g
Protein: 10g
Cholesterol: 85mg