Here's a great way to use summer's bounty of tomatoes and zucchini-by making a zucchini tomato casserole. Add this to your zucchini casserole recipes file. Layers of red ripe tomatoes and zucchini baked with a crunchy parmesan cheese herb topping; the best of summer vegetables all in one dish. Tomato and zucchini casserole is a great summer side dish. It's naturally gluten-free and make it dairy-free if preferred.
Looking for zucchini and tomato recipes? Try this one. Summer markets are overflowing with beautiful tomatoes, zucchini, and fresh herbs, so turn them into a casserole. It's sort of a traditional summer French dish called a vegetable tian but finished like a gratin, which is a fancy name for a casserole. Whatever you call it, make it! You'll be glad you did.
Jump to:
Why You'll Love Zucchini Tomato Casserole
- Zucchini & tomato - Two of summer's best in one delicious dish.
- Easy & wholesome - Simple ingredients, healthy prep, and satisfying results.
- Big flavor - Olive oil, garlic, herbs, and a golden Parmesan topping bring it all together.
- Dairy-free option - Swap in a vegan cheesy sprinkle for a plant-based version (recipe included).
What You'll Need
- Tomatoes - Use Roma tomatoes; they're meaty and less watery, perfect for layering without making the dish soggy.
- Zucchini - Choose zucchini similar in diameter to the tomatoes for a pretty, even presentation.
- Shallots - Add a mellow, sweet allium flavor that's softer than onions and classic in Provençal-style dishes.
- Cheese - Grated Parmigiano-Reggiano adds savory depth and a golden, crisp topping.
- Breadcrumbs - Use gluten-free or regular toasted breadcrumbs. They bring crunch and structure to the topping.
- Herbs - Fresh thyme leaves bring an earthy, aromatic note that pairs beautifully with tomatoes and zucchini.
- Garlic - Adds a punch of flavor-chop fine or zest for even distribution.
- Olive Oil - Extra virgin, used to coat the vegetables and finish the top for browning.
Please see the recipe card for measurements, salt, and pepper.
Chef's Tip: Homemade breadcrumbs are a thrifty, delicious way to use up leftover bread-and they taste so much better than store-bought. You control the texture, seasoning, and ingredients, plus they're easy to make and keep on hand. Use your favorite gluten-free or regular bread. Here's how to make homemade breadcrumbs.
Substitutions and Variations
- Herbs - Swap fresh thyme for fresh oregano, or use a dried blend called Herbes de Provence for a more traditional French flavor.
- Cheese - Parmesan is classic, but you can try pecorino Romano for a saltier bite, or skip the cheese entirely for a dairy-free version (see the recipe card).
- Breadcrumbs - Use your favorite gluten-free or regular breadcrumbs. For extra crunch and flavor, try panko (GF if needed) or homemade toasted crumbs (see Chef's Tip above).
- Add-ins - A few paper-thin slices of eggplant layer in beautifully if you want to expand the veggie mix.
How to Make Zucchini Tomato Casserole
Use either an oval casserole baking dish called a gratin, oval roaster, or a rectangular baking dish. Use a 3-4 quart size. The dish in the photo is approximately 13" long, 10" wide and 2 ½ " deep. For a rectangular casserole, arrange the vegetables in rows rather than an oval.
Slice the tomatoes and zucchini crosswise into about ¼" thick circles. Sauté shallot and garlic in olive oil until soft and place it in the bottom of the casserole, then top with overlapping layers of tomatoes and zucchini. Pack the slices fairly tight as they shrink during baking. Sprinkle the topping over the top and bake uncovered until golden, about 35-45 minutes. Serve to the happy smiles of your family.
Serving Suggestions
- As a side dish - Serve alongside grilled chicken, seared fish, or pork roast for a Provençal-inspired meal.
- With pasta or grains - Spoon over cooked quinoa, couscous, or polenta for a simple vegetarian main.
- For brunch - Pair with soft scrambled eggs or a poached egg on top and crusty bread on the side.
Another idea for summer tomatoes is tomato gazpacho soup. It's cool, refreshing and delicious!
📖 Recipe
Zucchini Tomato Casserole
Equipment
- casserole baking dish
Ingredients
- 6 Roma tomatoes about 1 ¼ pounds
- 3 zucchini about ¾ - 1 pound
- ¾ cup sliced shallots 1 large shallot
- ⅓ cup grated parmesan cheese
- 3 tablespoons breadcrumbs GF or wheat, as needed
- 1 ½ tablespoons fresh chopped thyme leaves
- 3 large garlic cloves finely chopped or zested
- ⅛ teaspoon sea salt
- ⅛ teaspoon ground black pepper
- 2 tablespoons extra virgin olive oil divided use
Instructions
Prep vegetables
- Pre-heat an oven to 375° degrees. Slice tomatoes and zucchini crosswise into approximately ¼" slices.
Cook shallot and garlic
- Add 1 tablespoon of olive oil to a small pan and heat oil over medium low heat. Add the shallot and cook until soft, about 2-3 minutes. Add garlic and cook another 30-60 seconds. Spread the soft shallots and garlic into the bottom of a 3-4 quart oval casserole.
Layer the vegetables
- Layer the tomato and zucchini slices alternately around the dish, starting at the outside and working in, overlapping tightly. Get as much as you can into the dish. You may not use quite all of the slices. Sprinkle with the salt and pepper.
Create topping
- Combine the parmesan, breadcrumbs, and herbs (or dairy-free sprinkle) then then scatter evenly over the top of the casserole. Drizzle with the last tablespoon of the olive oil.
Bake casserole
- Bake casserole until top is golden and crisp, about 35-45 minutes. Timing will depend on your oven. Serve warm.
Notes
Dairy-Free Cheesy Sprinkle (Parmesan Alternative)
- ½ cup raw, unsalted cashews
- 3 tablespoons nutritional yeast (Sari or Bragg)
- ¾ teaspoon granulated garlic (or ½ teaspoon garlic powder)
- ½ teaspoon fine sea salt (adjust to taste)
- Add all ingredients to a food processor or high-speed blender.
- Pulse until it forms a fine, crumbly texture like grated Parmesan-don't over-blend or it'll turn into a paste.
- Taste and adjust salt or garlic to preference.
- Store in an airtight jar in the fridge for up to a month.
Nutrition
Would you like to save this recipe?
Never lose a recipe! We'll email this post to you, so you can come back to it later.
Debbie in Alaska says
Do you think you could do this in a crockpot???
Sally Cameron says
Hi Debbie. I don't think a crock pot would work. This is an oven kind of recipe.
Denise says
Perfect! It looks delicious! I am testing different yeast powder for a best taste. I bought one that I didn't like at all. It smells bad! What brand are you using?
Sally Cameron says
Hi Denise. I bought it on Amazon, Sari Foods. Non-GMO, no synthetic vitamins, organic, really good. Think I put the link in the post. I will check the post right now for the cheesy sprinkle...