Zucchini Tomato Gratin with Golden Parmesan Crust

Zucchini Tomato Gratin is a simple, colorful baked vegetable side dish made with thin slices of zucchini, tomatoes, and potatoes layered over a garlicky tomato sauce. Finished with olive oil, Italian seasoning, and Parmesan cheese, this easy gratin is comforting enough for a family dinner and beautiful enough for a holiday table.

overhead shot of zucchini, tomato, and potato slices arranged accordion style in a baking dish.

An Easy and Healthy Baked Veggie Recipe

This zucchini tomato gratin is the kind of side dish that looks impressive but is very easy to prepare. The vegetables are sliced thinly, arranged in neat alternating rows, and baked until tender in a savory tomato base. It is a great way to serve fresh vegetables with very little effort, and the finished dish has a rustic, home-cooked look that works for both casual meals and special occasions.

The combination of red tomatoes, green zucchini, and pale potatoes gives this baked vegetable gratin a bright, inviting appearance. The flavor is simple and classic: tomato sauce, garlic, olive oil, Italian seasoning, salt, pepper, and a sprinkle of Parmesan cheese. As the vegetables bake, they soften and release their juices into the sauce, creating a bubbling, flavorful casserole-style side dish.

This recipe is also flexible. Serve it with roasted meats, poultry, pork, or as part of a vegetarian dinner. It is hearty enough to feel satisfying because of the potatoes, but still fresh and light thanks to the zucchini and tomatoes.

close up shot of zucchini slices, tomato slices, and potato slices arranged accordion style in a baking dish.

What You’ll Need

This easy zucchini, tomato, and potato gratin uses a short list of everyday ingredients. Since the recipe is so simple, good-quality vegetables and a flavorful tomato sauce will give you the best result.

Tomato Sauce: Use plain tomato sauce as the base of the gratin. Strained tomatoes can also work well.
Garlic: Fresh minced garlic adds bold flavor to the tomato sauce. Garlic powder can be used if needed.
Olive Oil: Olive oil enriches the sauce and helps the vegetables bake beautifully.
Italian Seasoning: A classic dried herb blend gives the dish a warm, savory flavor.
Tomatoes: Roma tomatoes or tomatoes on the vine are good choices because they slice neatly and bake well.
Zucchini: Use small zucchini and slice them into even rounds. Peeling is optional, but the skin adds color and texture.
Potatoes: Yukon gold potatoes are a great choice, but small white or red potatoes may also be used.
Salt and Pepper: Season to taste with salt and freshly ground black pepper.
Parmesan Cheese: Shredded Parmesan adds a salty, savory finish to the top of the gratin.
Fresh Parsley: A little chopped parsley makes a fresh, bright garnish before serving.

How to Make Zucchini Tomato Gratin

The key to a beautiful zucchini tomato gratin is slicing the vegetables evenly and arranging them upright in the baking dish. This helps them cook at the same pace and creates the attractive layered look.

Prepare the Oven and Sauce. Preheat the oven to 375˚F. In the bottom of a 2-quart baking dish, stir together the tomato sauce, minced garlic, 1 tablespoon olive oil, and 1 teaspoon Italian seasoning.
Arrange the Vegetables. Stand the sliced vegetables upright in the dish, alternating tomato, zucchini, and potato slices. Fit them closely together until the baking dish is full.
Season the Gratin. Sprinkle the remaining Italian seasoning over the vegetables. Add salt and freshly ground black pepper to taste, then drizzle with the remaining olive oil.
Bake Covered. Cover the baking dish with aluminum foil and bake for 35 minutes. This allows the potatoes and vegetables to soften without drying out.
Add Parmesan and Finish Baking. Remove the foil, sprinkle the Parmesan cheese over the top, and bake uncovered for another 20 to 30 minutes, or until the vegetables are tender and the sauce is bubbling.
Rest and Serve. Let the gratin stand for about 10 minutes before serving. Garnish with chopped fresh parsley and serve warm.

Tips for Success

These simple tips will help you make a tender, flavorful baked zucchini tomato gratin every time.

Slice Evenly: Try to keep the zucchini and tomatoes about ¼-inch thick and the potatoes about ⅛-inch thick. Potatoes take longer to cook, so thinner slices help them become tender.
Pack the Vegetables Tightly: Arrange the slices close together so they stay upright and bake into an attractive layered dish.
Add Onions: If you enjoy onions, add diced onions to the sauce or scatter them over the top before baking.
Add Crunch: For a crispier topping, mix a small amount of breadcrumbs or panko with the Parmesan cheese before sprinkling it over the gratin.
Watch the Cook Time: Ovens vary, and thicker vegetable slices may need extra time. Bake until the potatoes are tender and the sauce is hot and bubbly.

What to Serve with Zucchini Tomato Gratin

Zucchini tomato gratin is a versatile vegetable side dish that pairs well with many main courses. It is especially good with chicken, turkey, or pork, and it can also be served as part of a meatless meal with grains, salad, or another vegetable dish.

Chicken: Serve this gratin with baked, roasted, or stewed chicken for a comforting dinner.
Pork: The tomato, garlic, and Parmesan flavors pair nicely with pork chops or roasted pork.
Turkey: This colorful vegetable gratin is a lovely addition to a holiday-style turkey dinner.
Vegetarian Meals: Pair it with a green salad, pasta, rice, or beans for a satisfying vegetarian plate.

Can I Freeze Zucchini Tomato Gratin?

Freezing this zucchini tomato gratin is not recommended. Zucchini, tomatoes, and potatoes can release a lot of water after freezing and thawing, which may make the texture soft or mushy.

How to Store and Reheat Leftovers

Store leftovers in an airtight container, or cover the baking dish tightly. Keep refrigerated for 3 to 4 days.
Reheat in a 375˚F oven until the gratin is hot all the way through. Individual portions can also be reheated until warmed to your liking.

Enjoy this easy zucchini tomato gratin warm as a colorful, flavorful vegetable side dish.

Zucchini Tomato Gratin

Thin slices of zucchini, potatoes, and tomatoes are baked in a garlicky tomato sauce with olive oil, Italian seasoning, and Parmesan cheese.

Prep Time: 15 minutes

Cook Time: 1 hour

Resting Time: 10 minutes

Total Time: 1 hour 25 minutes

Servings: 8

Ingredients

1 cup tomato sauce
4 cloves garlic, minced
2 tablespoons olive oil, divided
2 teaspoons Italian seasoning, divided
3 to 4 tomatoes, cut into ¼-inch thick slices
2 small zucchini, cut into ¼-inch thick slices
3 to 4 small Yukon gold potatoes, cut into ⅛-inch thick slices
Salt and freshly ground black pepper, to taste
½ cup shredded Parmesan cheese
Chopped fresh parsley, for garnish

Instructions

Preheat the oven to 375˚F.
In the bottom of a 2-quart baking dish, mix the tomato sauce with the minced garlic, 1 tablespoon olive oil, and 1 teaspoon Italian seasoning.
Arrange the sliced tomatoes, zucchini, and potatoes upright in alternating rows. Fit the slices tightly together until the baking dish is filled.
Season the vegetables with the remaining Italian seasoning, salt, and freshly ground black pepper.
Drizzle the remaining olive oil over the vegetables.
Cover the dish with aluminum foil and bake for 35 minutes.
Remove the foil, sprinkle the Parmesan cheese over the top, and bake uncovered for 20 to 30 minutes, or until the vegetables are tender and the sauce is bubbling.
Remove from the oven and let the gratin stand for 10 minutes.
Garnish with chopped fresh parsley and serve warm.

Notes

For even slices, use a mandolin if you have one, and handle it carefully. Thin, consistent slices help the vegetables cook evenly.

Nutrition

Nutritional information is an estimate and may vary depending on the ingredients and tools used.

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