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Tomato Zucchini Casserole

Easy Cheesy Zucchini and Tomato Bake

Tomato Zucchini Casserole is a comforting, flavorful vegetable side dish that brings together fresh zucchini, juicy plum tomatoes, melted cheddar cheese, Parmesan, garlic, herbs, and a buttery breadcrumb topping. It is an easy way to turn everyday summer vegetables into a warm, cheesy casserole that feels homemade and satisfying.

 

  • Total Time: 55–65 minutes

Ingredients

Cheddar Cheese

Use 1 ½ cups grated Cheddar cheese for the main cheesy layer. Cheddar melts beautifully and provides a rich, familiar flavor that pairs naturally with both zucchini and tomatoes.

Sharp cheddar can be used when you want a stronger cheese flavor, while mild or medium cheddar creates a softer, more delicate taste.

Parmesan Cheese

You will need ⅓ cup grated Parmesan cheese. Parmesan adds salty, savory flavor and complements the cheddar while also contributing to the golden topping.

For the best texture, freshly grated Parmesan is an excellent option.

Garlic

Use 2 cloves minced garlic. Fresh garlic adds depth and a wonderful savory aroma to the casserole.

If you prefer a milder garlic flavor, reduce the amount slightly. If you love garlic, you can add an additional clove.

Dried Oregano

Add ½ teaspoon dried oregano. Oregano gives the casserole a Mediterranean-inspired flavor that works especially well with tomatoes.

Dried Basil

Use ½ teaspoon dried basil to add a mild herbal sweetness and complement the tomato flavor.

Salt and Pepper

Season with salt and pepper to taste. Because Parmesan and cheddar already contain salt, season gradually.

Zucchini

Use 2 medium zucchini, thinly sliced. Try to slice the zucchini evenly so that all the pieces cook at approximately the same rate.

Plum Tomatoes

You will need 5 plum tomatoes, thinly sliced. Plum tomatoes are a good choice because they tend to be meaty and work well in baked dishes.

Butter

Use ¼ cup butter to create the rich breadcrumb topping. Melted butter helps the breadcrumbs become golden and crisp during baking.

Onion

Add 2 tablespoons finely chopped onion for extra savory flavor.

Fine Breadcrumbs

Use ¾ cup fine breadcrumbs for the casserole topping. The breadcrumbs absorb some of the buttery flavor and create a crisp contrast against the tender vegetables and melted cheese.

Instructions

Step 1: Prepare the Vegetables

Begin by washing the zucchini and tomatoes thoroughly and patting them dry.

Thinly slice the 2 medium zucchini and 5 plum tomatoes. Try to keep the slices relatively uniform in thickness.

Even slices help the vegetables cook evenly and make the finished casserole look more attractive when layered in the baking dish.

If your zucchini is particularly watery, you can lightly pat the slices with paper towels before assembling the casserole. This can help reduce excess moisture.

Step 2: Prepare the Cheese Mixture

In a bowl, combine the 1 ½ cups grated cheddar cheese and ⅓ cup grated Parmesan cheese.

Add the 2 minced garlic cloves, ½ teaspoon dried oregano, and ½ teaspoon dried basil.

Season with salt and pepper to taste.

Mix everything thoroughly so the garlic and herbs are evenly distributed throughout the cheese.

This mixture will provide the main savory flavor for the casserole.

Step 3: Layer the Zucchini and Tomatoes

Lightly grease a suitable baking dish.

Arrange a layer of sliced zucchini in the bottom of the dish. Follow with a layer of sliced tomatoes.

Sprinkle part of the cheddar-Parmesan mixture over the vegetables.

Continue layering the zucchini, tomatoes, and cheese mixture until the ingredients have been used.

Try not to pack the vegetables too tightly. A little space between the slices allows heat to circulate and helps the casserole cook evenly.

Step 4: Prepare the Breadcrumb Topping

Melt the ¼ cup butter in a small pan or microwave-safe bowl.

Add the 2 tablespoons finely chopped onion and ¾ cup fine breadcrumbs.

Mix until the breadcrumbs are evenly coated with butter and the onion is distributed throughout.

The butter is important because it helps the breadcrumbs turn golden and crisp while baking.

Step 5: Add the Topping and Bake

Spread the buttery breadcrumb mixture evenly over the top of the casserole.

Make sure the breadcrumbs cover the surface without creating an excessively thick layer.

Place the casserole in a preheated oven and bake until the zucchini and tomatoes are tender, the cheese is melted and bubbling, and the breadcrumb topping is golden brown.

Cooking time can vary depending on the depth of the casserole and your oven, so begin checking toward the end of the expected cooking time.

Once finished, remove the casserole from the oven and allow it to rest for several minutes before serving.

Notes

The biggest consideration when preparing Tomato Zucchini Casserole is the natural moisture in the vegetables.

Zucchini and tomatoes both release water as they cook. This is completely normal, but excessive moisture can make the finished casserole watery.

For the best results, slice the vegetables relatively thinly and evenly. If your zucchini is very moist, gently pat the slices dry before assembling the casserole.

  • Author: Kelly
  • Prep Time: 20 minutes
  • Cook Time: 35–45 minutes