Quick Recipe Version (TL;DR)
Quick Ingredients
- 2 tbsp olive oil, plus 1/4 cup for drizzle
- 1 small onion, finely chopped
- 6 cloves garlic, minced (divided)
- 1 can (14.5 oz / 400 g) crushed tomatoes
- 1 tbsp tomato paste
- 2 medium zucchini (about 1 lb / 450 g)
- 2 small eggplants (about 1 1/4 lb / 570 g total)
- 4–5 medium tomatoes (about 1 1/2 lb / 680 g)
- 2 bell peppers (red, yellow, or orange)
- 1 tsp dried oregano, 1/2 tsp dried thyme
- 1/4 tsp red pepper flakes (optional)
- 1/4–1/2 cup fresh basil leaves, chopped or torn
- Salt, black pepper, and 1–2 tbsp grated Parmesan (optional)
Do This
- 1. Preheat oven to 375°F (190°C). Lightly oil a 9×13-inch (23×33 cm) or similar baking dish.
- 2. Make a quick sauce: sauté onion and some garlic in 2 tbsp olive oil, add crushed tomatoes, tomato paste, dried herbs, salt, and pepper; simmer 5–8 minutes. Spread in the baking dish.
- 3. Slice zucchini, eggplant, and tomatoes into 1/4-inch (6 mm) rounds; cut bell peppers into thin strips or rings. Lightly season with salt and pepper.
- 4. In a bowl, mix 1/4 cup olive oil with remaining garlic, red pepper flakes, chopped basil, salt, and pepper.
- 5. Arrange vegetables upright in tight overlapping rows over the sauce, alternating colors for a striped effect.
- 6. Drizzle garlic–herb oil evenly over the vegetables. Cover with foil and bake 30–35 minutes.
- 7. Uncover and bake 20–25 minutes more, until tender and lightly browned. Rest 10 minutes, garnish with more basil and optional Parmesan, then serve warm.
Why You’ll Love This Recipe
- It turns simple, inexpensive vegetables into a stunning centerpiece that looks straight out of a cozy farmhouse kitchen.
- The garlic–olive oil drizzle and fresh basil add big flavor without complicated steps.
- It is naturally light yet satisfying, perfect as a vegetarian main or colorful side.
- You can prep it ahead, and leftovers taste even better the next day.
Grocery List
- Produce: Zucchini, eggplant, tomatoes, red and/or yellow bell peppers, onion, garlic, fresh basil, fresh parsley (optional).
- Dairy: Parmesan cheese (or vegetarian/vegan hard cheese), optional for finishing.
- Pantry: Extra-virgin olive oil, canned crushed tomatoes, tomato paste, dried oregano, dried thyme, red pepper flakes, sugar (optional), salt, black pepper.
Full Ingredients
For the Base Tomato Sauce
- 2 tbsp olive oil
- 1 small yellow onion, finely chopped (about 1/2 cup / 75 g)
- 3 cloves garlic, minced
- 1 can (14.5 oz / 400 g) crushed tomatoes
- 1 tbsp tomato paste
- 1 tsp dried oregano
- 1/2 tsp dried thyme
- 1/2 tsp kosher salt (or 1/4 tsp fine salt), plus more to taste
- 1/4 tsp freshly ground black pepper
- 1/2 tsp sugar (optional, to balance acidity)
For the Vegetable Layers
- 2 medium zucchini (about 1 lb / 450 g), trimmed and sliced into 1/4-inch (6 mm) rounds
- 2 small Italian or globe eggplants (about 1 1/4 lb / 570 g total), sliced into 1/4-inch (6 mm) rounds
- 4–5 medium ripe tomatoes (about 1 1/2 lb / 680 g), sliced into 1/4-inch (6 mm) rounds
- 2 bell peppers (red, yellow, or orange), cored and sliced into thin rings or strips
- 1/2 tsp kosher salt (for seasoning vegetables)
- 1/4 tsp freshly ground black pepper
For the Garlic–Olive Oil Drizzle
- 1/4 cup extra-virgin olive oil
- 3 cloves garlic, very finely minced or grated
- 1/4 tsp red pepper flakes (optional, for gentle heat)
- 2 tbsp fresh basil, finely chopped
- 1 tbsp fresh parsley, finely chopped (optional)
- 1/2 tsp kosher salt
- 1/4 tsp freshly ground black pepper
To Finish
- 1/4–1/3 cup loosely packed fresh basil leaves, torn or thinly sliced (for garnish)
- 1–2 tbsp freshly grated Parmesan or vegetarian hard cheese (optional)
- Flaky sea salt and freshly ground black pepper, to taste
Step-by-Step Instructions
Step 1: Preheat the oven and prepare the baking dish
Preheat your oven to 375°F (190°C) with a rack in the center. Lightly oil a 9×13-inch (23×33 cm) baking dish or a similar 2–3 quart (2–3 L) shallow casserole. A white or light-colored dish shows off the vegetable colors beautifully, but any oven-safe dish will work.
Step 2: Make the simple tomato base
In a medium skillet, heat 2 tbsp olive oil over medium heat. Add the chopped onion and cook, stirring occasionally, until it is soft and lightly translucent, about 4–5 minutes. Stir in 3 minced garlic cloves and cook for another 30 seconds until fragrant, being careful not to brown the garlic.
Add the crushed tomatoes, tomato paste, dried oregano, dried thyme, salt, black pepper, and optional sugar. Stir well and let the sauce simmer gently for 5–8 minutes, until slightly thickened and flavorful. Taste and adjust seasoning if needed. Pour the sauce into the prepared baking dish and spread it into an even layer that covers the bottom.
Step 3: Slice and season the vegetables
While the sauce is simmering, slice the vegetables. Trim the ends of the zucchini and eggplant, then cut them into 1/4-inch (6 mm) thick rounds. Slice the tomatoes the same thickness. Core the bell peppers and cut them into thin rings or strips, discarding seeds and white membranes.
Place all the sliced vegetables on a large tray or sheet pan. Lightly sprinkle with 1/2 tsp kosher salt and 1/4 tsp black pepper, tossing gently so everything is lightly and evenly seasoned. If any slices are very wet (especially the eggplant), pat them dry with a paper towel so the casserole does not become watery.
Step 4: Mix the garlic–olive oil drizzle
In a small bowl or measuring cup, combine 1/4 cup extra-virgin olive oil, 3 minced garlic cloves, red pepper flakes (if using), chopped basil, chopped parsley (if using), 1/2 tsp kosher salt, and 1/4 tsp black pepper. Stir well to combine. This mixture should smell very fragrant and garlicky. Set aside; it will be drizzled over the vegetables before baking.
Step 5: Layer the vegetables in the dish
With the tomato sauce already spread in the baking dish, start arranging the vegetables on top. Take one slice each of zucchini, eggplant, and tomato, plus a piece of bell pepper, and stack them loosely together in your hand so they form a small, colorful stack. Place this stack upright in the sauce along the edge of the dish so the rounded edges are facing up and the slices slightly fan out.
Continue stacking and arranging the vegetables in tight, overlapping rows, alternating colors and types as you go (for example, zucchini, eggplant, tomato, pepper, repeat). Work your way around the edge of the dish and then into the center until all the sauce is covered in a shingled pattern of vegetables. If you have extra slices, tuck them into any gaps.
Step 6: Drizzle with garlic oil and bake
Give the garlic–olive oil mixture a quick stir, then slowly drizzle it evenly over the entire surface of the vegetables, trying to distribute the garlic and herbs as well as the oil. Cover the dish tightly with aluminum foil. Bake in the preheated oven for 30–35 minutes, until the vegetables begin to soften and release their juices.
Remove the foil and return the dish to the oven. Bake uncovered for another 20–25 minutes, until the vegetables are very tender, the edges are lightly browned, and the tomato sauce is bubbling around the sides. If you like a deeper caramelized top, you can place the dish under the broiler for 2–3 minutes, watching carefully so it does not burn.
Step 7: Rest, garnish, and serve
Remove the casserole from the oven and let it rest for 10 minutes. This rest time helps the juices settle and makes it easier to serve neat portions. Just before serving, scatter the top with the torn basil leaves and, if using, a light dusting of freshly grated Parmesan. Finish with a pinch of flaky sea salt and a few grinds of black pepper.
Serve warm as a rustic vegetarian main with crusty bread, polenta, or a simple green salad, or as a colorful side dish alongside grilled or roasted meats.
Pro Tips
- Slice evenly: Try to keep all vegetable slices about 1/4-inch (6 mm) thick so they cook at the same rate and layer neatly.
- Use firm, ripe tomatoes: Overly soft tomatoes can make the dish watery; choose tomatoes that are ripe but still hold their shape when sliced.
- Do not skimp on salt: Proper seasoning brings out the sweetness of the vegetables. Taste the sauce and lightly season the veggies before assembling.
- Pack the layers snugly: The tighter the shingled rows, the more beautiful the pattern and the less the vegetables will slump as they bake.
- Let it rest before cutting: Those 10 minutes after baking help the juices settle and make serving tidy, restaurant-style wedges much easier.
Variations
- Cheesy top: In the last 10 minutes of baking, sprinkle the casserole with 1/2–3/4 cup shredded mozzarella, Gruyère, or a plant-based cheese for a gratin-style finish.
- Herb swap: Replace basil with a mix of fresh thyme and rosemary for a deeper, more woodsy flavor, or add a spoonful of pesto to the garlic–olive oil drizzle.
- Protein boost: Spread a layer of cooked lentils, white beans, or crumbled cooked sausage over the tomato sauce before adding the vegetables for a heartier main dish.
Storage & Make-Ahead
Let the casserole cool completely, then cover tightly and refrigerate for up to 4 days. Reheat individual portions in the microwave or warm the whole dish in a 325°F (165°C) oven, covered, for about 20 minutes, or until heated through.
For make-ahead prep, you can fully assemble the dish (through drizzling the garlic–olive oil) up to 24 hours in advance. Cover and refrigerate, then bake directly from the fridge, adding an extra 5–10 minutes to the covered baking time. Leftovers also freeze reasonably well: wrap tightly and freeze for up to 2 months. Thaw overnight in the refrigerator before reheating.
Nutrition (per serving)
Approximate values for 1 of 6 servings (without Parmesan): 220 calories; 15 g fat; 20 g carbohydrates; 5 g protein; 5 g fiber; 460 mg sodium. Adding cheese will slightly increase calories, fat, and sodium. Values are estimates and will vary with exact ingredients and brands used.
