I can’t wait to share my Tomato Eggplant Zucchini Bake, a French tian that arranges summer zucchini, eggplant and tomatoes into a colorful baked casserole gratin with a surprising twist.

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I can’t resist a pile of summer produce, and this colorful gratin grew from that urge. I love how zucchini and eggplant sit side by side, their colors layering like a painter messed up on purpose.

It looks fancy but is honest, not precious, and there’s a slight char smell that makes you curious. I’ve riffed on Roasted Eggplant And Zucchini Recipes for years and once borrowed a twist from a Tomato Eggplant Zucchini Bake With Garlic And Parmesan I tasted at a bistro.

Every time I make it people ask whats in it before they even take a fork.

Ingredients

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Spongy eggplant soaks flavors, low calorie, good fibre, slightly bitter when undercooked
Tender zucchini add moisture, mild sweet notes, vitamin C and potassium boost
Juicy tomatoes bring acidity, natural sweetness, lycopene antioxidant and bright color
Sweet onion caramelize, deepens flavor, provides fiber and savory backbone
Garlic punch up aroma, antibacterial compounds, small amount adds big flavor
Extra virgin olive oil give silkiness, healthy monounsaturated fats, warms flavors
Grated Parmesan or Gruyere melt golden, salty umami, adds protein and richness
Fresh basil finish bright, herbaceous lift, vitamin K and aromatic oils

Ingredient Quantities

1 large eggplant (about 450 g)

3 medium zucchini (about 600 g)

4 medium ripe tomatoes (about 500 g)

1 medium yellow onion (about 150 g)

3 garlic cloves

3 tablespoons extra virgin olive oil

1 teaspoon dried herbes de Provence or 1 tablespoon fresh thyme leaves

1/2 cup freshly grated Parmesan or Gruyere (about 50 g)

1/4 cup fresh breadcrumbs or panko (about 25 g)

Kosher salt and freshly ground black pepper to taste

A handful fresh basil or parsley leaves for garnish

How to Make this

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1. Preheat oven to 190C (375F). Lightly oil a 9 by 13 inch or similar shallow baking dish with 1 tablespoon of the olive oil.

2. Slice the eggplant, zucchini and tomatoes into even 1/8 to 1/4 inch rounds. Slice the onion thinly and mince the 3 garlic cloves. If your eggplant is large, sprinkle the slices with kosher salt and let them sit 10 to 15 minutes to draw out moisture, then rinse and pat dry well with paper towels.

3. Heat 1 tablespoon olive oil in a small skillet over medium heat, add the sliced onion and cook until soft and translucent, about 5 minutes. Add the minced garlic and the herbes de Provence or fresh thyme, cook 30 seconds more, season lightly with salt and pepper. Spread this onion mixture in an even layer on the bottom of the prepared dish.

4. Arrange the vegetable slices upright in the dish, alternating zucchini, eggplant and tomato, packed close together so they stand in rows. Try to keep them uniform for even cooking, but it doesnt have to be perfect.

5. Drizzle the remaining 1 tablespoon olive oil over the arranged vegetables, then sprinkle a bit more kosher salt and freshly ground black pepper over the top.

6. Cover the dish tightly with foil and bake for 25 to 30 minutes, until the vegetables are tender and release some juices.

7. While the tian bakes, mix the grated Parmesan or Gruyere with the breadcrumbs and a pinch of black pepper. If the mixture seems dry add a teaspoon of olive oil to help it clump.

8. Remove the foil, sprinkle the cheese and breadcrumb mix evenly over the top, then return the dish to the oven uncovered for 10 to 15 minutes until the topping is golden and bubbling.

9. Let the gratin rest 8 to 10 minutes so it sets a bit, then scatter the torn basil or parsley leaves over the top, adjust salt and pepper if needed and serve warm or at room temperature.

Equipment Needed

1. 9 by 13 inch shallow baking dish (or similar)

2. Sharp chef’s knife for even slicing

3. Cutting board

4. Mandoline or very sharp paring knife for thin, uniform rounds (optional but super helpful)

5. Small skillet for softening the onion

6. Small mixing bowl and fork to combine cheese and breadcrumbs

7. Box grater for the Parmesan or Gruyere

8. Measuring spoons and a tablespoon measure for the oil

9. Aluminum foil and oven mitts for safe handling and covering the dish

(You can swap the mandoline for extra patience if you dont have one)

FAQ

Q: Can I swap the Parmesan for something else? A: Yes. Gruyere is a great swap, it melts creamier and gives a nuttier flavor. Pecorino works too but tastes saltier so use a bit less salt in the dish.

Q: My vegetables make a lot of liquid, how do I stop a soggy gratin? A: Salt the sliced eggplant and zucchini and let them sit for 20 to 30 minutes, then pat dry with paper towels. Also slice tomatoes a bit thinner and drain excess seeds if they look juicy, that helps a lot.

Q: Can I make this ahead of time or freeze it? A: You can assemble it up to 24 hours ahead, cover and chill, then bake straight from the fridge adding 5 to 10 extra minutes. For freezing, bake first, cool completely, wrap well and freeze up to three months. Reheat in a 350 F oven until warmed through.

Q: What oven temp and baking time should I use for even cooking? A: Bake at 375 F about 35 to 45 minutes until veggies are tender and top is golden. If top browns too fast tent loosely with foil and finish cooking until interior is done.

Q: Any good substitutions for breadcrumbs or if I need gluten free? A: Use panko or regular breadcrumbs for crunch, or swap with crushed gluten free crackers or almond meal for a gluten free option. A little extra cheese also helps create a nice crust.

Q: How should I store and reheat leftovers? A: Keep leftovers in an airtight container in the fridge for up to four days. Reheat in a 350 F oven for 15 to 20 minutes so it warms evenly, or microwave for a quick single serving though the top wont stay crisp.

Use Up Summer’s Bounty In This Colorful, Zucchini, Eggplant, Tomato Gratin Recipe Substitutions and Variations

Eggplant: swap for thick portobello mushroom caps or 2 medium yellow summer squash, both roast up nicely and soak in flavors
Zucchini: use pattypan or crookneck squash for a similar texture, or try 1 small fennel bulb if you want a mild anise note
Tomatoes: substitute one 14 ounce can diced or crushed tomatoes, lightly drained, or 2 cups halved cherry tomatoes for sweeter bite
Fresh Parmesan or Gruyere: use Pecorino Romano for a sharper saltier kick or fontina for extra melt and creaminess, grated Asiago also works

Pro Tips

1) Salt the eggplant right but dont overdo it. For big eggplants salt and let them sit 10–15 minutes then rinse and pat dry well, or if youre in a hurry sear slices 1 minute per side in a hot pan to shrink water and add flavor. Be sure theyre dry before arranging or the dish will get soggy.

2) Keep the slices even, a mandoline or a sharp knife helps. If they arent perfect pack them tight so they support each other, and if some fall over just lay those flat, theyll still bake fine.

3) Prevent a wet, limp topping by pouring off excess juices after the covered bake or blotting with a paper towel before you add the cheese/breadcrumb mix. Also toss the crumbs with a little olive oil or melted butter so they brown and crisp instead of turning mushy.

4) Layer the flavors: sweat the onion longer for sweetness, add a tiny pinch of sugar if your tomatoes are very acidic, and always finish with fresh herbs and a squeeze of lemon or a splash of good vinegar right before serving. Let the gratin rest 8–10 minutes so it sets, otherwise it will fall apart when you try to plate it.

Use Up Summer's Bounty In This Colorful, Zucchini, Eggplant, Tomato Gratin Recipe

Recipe by Nikoli Athen

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I can’t wait to share my Tomato Eggplant Zucchini Bake, a French tian that arranges summer zucchini, eggplant and tomatoes into a colorful baked casserole gratin with a surprising twist.

Servings

servings

Calories

175

kcal

Equipment: 1. 9 by 13 inch shallow baking dish (or similar)