01 -
Preheat oven to 375°F. Generously grease a 9x9-inch baking dish using nonstick cooking spray or softened butter.
02 -
Slice the zucchinis into uniform thin rounds. If excess moisture is present, gently blot slices with paper towels to remove water.
03 -
In a large mixing bowl, whisk together the sour cream, mayonnaise, eggs, garlic powder, onion powder, salt, and black pepper until thoroughly combined.
04 -
Add shredded mozzarella, cheddar, and grated Parmesan to the bowl. Stir until all cheeses are well distributed through the mixture.
05 -
Fold the sliced zucchini into the cheese mixture, ensuring each piece is completely coated.
06 -
Pour the zucchini-cheese mixture into the prepared baking dish and spread evenly across the surface.
07 -
If desired, sprinkle breadcrumbs evenly over the top for added texture and crunch.
08 -
Place dish on the center oven rack and bake for 35 to 40 minutes, or until the top is golden and the casserole is set in the center.