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Zucchini Parmesan Casserole with Roasted Slices and Golden-Browned Cheese Pinterest recipe pin

Zucchini Parmesan Casserole

Layered zucchini slices roasted briefly, simmered marinara, and a mozzarella-Parmesan topping baked until bubbly for a firm, sliceable casserole.
Print Recipe Pin Recipe
Prep Time 25 minutes
Cook Time 42 minutes
Total Time 1 hour 17 minutes
Servings: 6 servings
Calories: 320
Ingredients Equipment Method Notes

Ingredients
  

  • 4 medium zucchini about 2 pounds, trimmed and sliced 1/4-inch thick
  • 2 tablespoons olive oil divided
  • 1 teaspoon kosher salt divided
  • 1/2 teaspoon black pepper divided
  • 1 small yellow onion finely diced (about 1 cup)
  • 2 cloves garlic minced
  • 24 ounces jarred tomato sauce or 14 ounces crushed tomatoes + 1 tablespoon tomato paste
  • 1 teaspoon dried oregano
  • 1/2 teaspoon dried basil
  • 1/4 teaspoon sugar optional
  • 1 tablespoon fresh parsley chopped (optional)
  • 3 cups shredded low-moisture mozzarella cheese divided
  • 3/4 cup freshly grated Parmesan cheese divided
Optional topping
  • 3/4 cup panko breadcrumbs optional for topping
  • 1 tablespoon butter melted (optional for topping)

Equipment

  • 1 9×13-inch baking dish
  • 1 Half-sheet pan
  • 1 10-inch skillet
  • 1 Box grater

Method
 

Prep and roast zucchini
  1. Preheat oven to 425°F; toss zucchini slices with 1 tablespoon olive oil, 1/2 teaspoon kosher salt, and 1/4 teaspoon black pepper; spread in a single layer on a rimmed sheet pan and roast 8–10 minutes, turning once, until edges are lightly golden; transfer to paper towels and rest 5 minutes.
Make the sauce
  1. Heat remaining 1 tablespoon olive oil in a 10-inch skillet over medium heat; cook diced onion until translucent, about 5 minutes, add garlic and cook 30 seconds; stir in tomato sauce (or crushed tomatoes + tomato paste), oregano, basil, remaining 1/2 teaspoon salt, 1/4 teaspoon black pepper, and sugar; simmer 8–12 minutes until slightly thickened, remove from heat and stir in parsley if using.
Assemble and bake
  1. Lower oven to 400°F; spread 1 cup sauce in the bottom of a 9×13-inch baking dish; layer one-third of the roasted zucchini in an even layer, sprinkle with 1 cup mozzarella and 1/4 cup Parmesan, spoon 1 cup sauce over cheese; repeat two more times ending with cheese on top; cover loosely with foil and bake 20 minutes, remove foil and bake 10–12 minutes until cheese is bubbly and edges brown; let rest 10 minutes before slicing.
Optional topping
  1. If using panko topping, mix panko with melted butter and sprinkle over cheese before the final uncovered bake; bake as directed until crumbs are golden.

Notes

Salt and roast the zucchini first to avoid excess moisture; a slightly reduced sauce prevents a watery bake. Let the casserole rest 10 minutes before slicing so it holds together. To freeze, assemble unbaked, cover tightly, and freeze up to 3 months; thaw overnight before baking and add 5–10 minutes to the covered bake time.