This zucchini tomato casserole is the kind of simple, summery dish that makes weeknights feel special. It’s packed with tender zucchini, juicy tomatoes, a hint of garlic, and a light layer of cheese and herbs. The texture is soft but not soggy, with a golden top that smells incredible coming out of the oven.
Serve it as a meatless main or as a bright side next to grilled chicken or fish. It’s easy to assemble, easy to love, and easy to customize with what you have on hand.
What Makes This Recipe So Good
- Fresh, seasonal flavors: Zucchini and tomatoes shine when baked gently with olive oil, garlic, and herbs.
- Light but satisfying: It feels wholesome and nourishing without being heavy.
- Minimal prep: Slice, layer, season, and bake. No complicated steps.
- Flexible and forgiving: Works with different cheeses, herbs, and even add-ins like onions or bell peppers.
- Great for meal prep: Reheats well and tastes even better on day two as the flavors settle.
What You’ll Need
- 2 medium zucchini, thinly sliced (about 1/8-inch thick)
- 3–4 medium ripe tomatoes, thinly sliced
- 1 small yellow onion, thinly sliced (optional but recommended)
- 2–3 cloves garlic, minced
- 2 tablespoons olive oil, plus more for drizzling
- 1/2 teaspoon kosher salt, plus more to taste
- 1/4 teaspoon black pepper
- 1 teaspoon dried Italian seasoning or herbes de Provence
- 1/4 teaspoon red pepper flakes (optional, for a little heat)
- 1/3 cup grated Parmesan cheese
- 1/2 cup shredded mozzarella or fontina
- 2 tablespoons fresh basil or parsley, chopped (for garnish)
- 1 tablespoon balsamic vinegar (optional, for finishing)
Instructions
- Preheat the oven: Set to 375°F (190°C).
Lightly oil a 9×9-inch baking dish or similar-sized casserole.
- Prep the vegetables: Slice zucchini and tomatoes into even, thin rounds. Pat the tomato slices dry with a paper towel to reduce excess moisture.
- Season the base: In a small bowl, mix olive oil, minced garlic, salt, pepper, Italian seasoning, and red pepper flakes. Spread a spoonful over the bottom of the dish.
- Layer the veggies: Arrange alternating slices of zucchini, tomato, and onion upright in rows or in a spiral.
Pack them snugly so they support each other.
- Brush and season: Spoon or brush the remaining oil-and-garlic mixture over the vegetables. Sprinkle with half the Parmesan.
- Cover and bake: Cover loosely with foil and bake for 20 minutes to soften the vegetables without browning too fast.
- Add cheese: Remove the foil. Sprinkle mozzarella and the remaining Parmesan over the top.
- Bake until golden: Return to the oven, uncovered, for 15–20 minutes, until the cheese is melted and lightly browned and the vegetables are tender.
- Finish: Let the casserole rest for 10 minutes.
Drizzle with a little olive oil or balsamic if using, and shower with fresh basil or parsley.
- Serve: Cut into squares or spoon out gently. It pairs well with crusty bread, a simple green salad, or grilled protein.
Storage Instructions
- Refrigerate: Cool completely, then store in an airtight container for up to 4 days.
- Reheat: Warm in a 325°F (165°C) oven until hot, about 15 minutes, or microwave in short bursts. Add a splash of olive oil to refresh.
- Freeze: Not ideal due to the high water content, but possible.
Freeze tightly wrapped for up to 2 months. Thaw overnight and reheat in the oven to reduce sogginess.
Health Benefits
- Low in calories, big on nutrients: Zucchini is rich in vitamin C, potassium, and fiber. Tomatoes add lycopene and antioxidants.
- Heart-friendly fats: Olive oil brings monounsaturated fats that support heart health.
- Protein and calcium boost: Cheese adds a modest amount of protein and calcium without overwhelming the dish.
- Vegetable-forward: A tasty way to increase daily veggie intake, especially during peak summer.
Pitfalls to Watch Out For
- Watery casserole: Tomatoes release liquid.
Pat them dry and avoid overly thick slices. Don’t overload the pan.
- Uneven cooking: Slice vegetables evenly. Thinner, consistent rounds cook at the same rate.
- Bland flavor: Season in layers.
Salt the oil mixture, use herbs generously, and finish with fresh basil.
- Burnt top, raw middle: Start covered, then uncover to brown. This softens the vegetables before the cheese goes on.
Variations You Can Try
- Herb-forward: Swap Italian seasoning for fresh thyme and rosemary. Add a squeeze of lemon before serving.
- Cheesy upgrade: Use goat cheese crumbles and Parmesan for a tangy, creamy finish.
Or try fontina for extra melt.
- Breadcrumb crunch: Mix panko with a drizzle of olive oil and a pinch of salt. Sprinkle on top for the last 10 minutes of baking.
- Mediterranean touch: Add sliced olives, capers, and a dusting of feta. Finish with oregano and a splash of red wine vinegar.
- Protein add-in: Layer in cooked chicken sausage or white beans for a heartier main.
- Extra veg: Add thinly sliced bell peppers or eggplant.
If using eggplant, salt and pat dry first.
FAQ
Can I make this casserole ahead of time?
Yes. Assemble up to the point before adding cheese, cover, and refrigerate for up to 24 hours. When ready to bake, add 5–10 extra minutes, then top with cheese and finish uncovered.
How do I prevent it from getting soggy?
Slice the vegetables thinly and evenly, pat tomato slices dry, and avoid overcrowding.
Baking covered first softens the veg, then baking uncovered evaporates excess moisture.
Which tomatoes work best?
Firm, ripe tomatoes like Roma or plum tomatoes release less liquid and hold shape. Heirlooms taste great but can be juicier, so blot them well.
Can I make it dairy-free?
Absolutely. Skip the cheese or use a dairy-free shredded cheese.
Add extra herbs and a crunchy breadcrumb topping for texture and flavor.
What can I serve with it?
It’s great with grilled chicken, salmon, or a simple quinoa salad. A slice of crusty bread to soak up the juices is always welcome.
Is peeling the zucchini necessary?
No. The peel is tender and adds color and fiber.
Just wash the zucchini well and slice.
Can I use canned tomatoes?
Not ideal for this recipe. Fresh slices are key to the layered look and texture. If you must, drain them very well and expect a softer result.
Final Thoughts
This zucchini tomato casserole is simple food done right: fresh ingredients, clean seasoning, and a cozy bake that brings it all together.
It’s the kind of dish you can rely on when you want something wholesome without a lot of fuss. Keep it classic or play with the variations and make it your own. Either way, it delivers bright flavor in every bite and fits almost any table, any night of the week.
Enjoy it warm today and love the leftovers tomorrow.