Oh my. Look who's getting all fancy with the vegetables!
It's as if my garden decided to throw a prom, and the eggplants, zucchini, and tomatoes banded together to show everyone else up. (Clearly, they deserve best prize for something, don't you think?)
Normally I would look at something like this and think it's waaaay too complicated. But this summer vegetable gratin is actually quite straightforward.
To prepare these vegetables, you have to cut them anyway, so why not cut them in rounds and arrange them in a pretty pattern?
Ratatouille or Tian Recipe?
If you recall, Remy, the "little chef" in Pixar's Ratatouille, prepared something similar for Anton Ego, the food critic. This isn't that dish, but something much easier.
You just sauté onions and bell peppers, layer them at the bottom of a casserole dish, top with rounds of eggplant, zucchini, and tomato. Top that with cheese and bake!
It's a lovely, easy, colorful presentation for our favorite summer vegetables. A perfect side to take to a party.
Swaps and Substitutions
This versatile recipe can handle switching things up according to your personal taste or what fresh vegetables you have on hand.
- Substitute yellow squash for the eggplant or zucchini.
- Sauté sliced mushrooms with the onion and bell pepper.
- Replace the ripe tomatoes with green tomatoes.
- Use other fresh herbs, such as rosemary or thyme, in place of or in addition to the parsley.
- Use mozzarella, cheddar, or crumbled goat cheese in place of the provolone.
Slicing Vegetables for This Gratin
The zucchini, eggplant, and tomato in this recipe need to be sliced into 1/4-inch rounds. A mandolin will make short work of slicing the eggplant and tomato evenly and quickly. You can also use a food processor with a slicing disc. Slicing the vegetables evenly is a big part of this gratin's visual appeal, and ensures the veggies all cook at the same rate.
Very large tomatoes may need to be cut in half or into quarters so their diameter is close to that of the zucchini and eggplant.
How to Prepare This Tian in Advance
You can cut the onions, bell pepper, tomato, eggplant, and zucchini up to 1 day ahead to save prep time.
Or, assemble the dish up to 1 day in advance, but don't bake. Sauté the onion and bell pepper in two tablespoons of olive oil and place in the gratin dish. Allow to cool completely before topping with the remaining ingredients except for the remaining one tablespoon of olive oil. Cover tightly with foil and refrigerate up to 1 day. Remove from the refrigerator 1 hour before baking to let the dish come to room temperature. Drizzle with olive oil right before baking.
Storing Leftovers Gratin
Cover the dish and refrigerate 3 to 5 days. Reheat individual portions in the microwave or the entire dish in the oven at 350°F until just warmed through.
We don't recommend freezing this dish. The texture of the vegetables won't hold up once defrosted.
5 More Vegetable Side Dishes You'll Love
- Brussels Sprouts Gratin
- Beet Greens
- Braised Leeks
- Summer Squash Green Chile Stir Fry
- Grilled English Peas
Zucchini, Eggplant, Tomato Gratin
We're topping this gratin with provolone and Parmesan cheeses. You could easily top it with gruyere instead. For a more Provençal approach, skip the cheese altogether and top with bread crumbs, minced garlic, parsley, and olive oil.
- 3 tablespoons extra virgin olive oil, divided
- 2 cups sliced yellow onion (about 1 large onion)
- 1 cup sliced red, orange, or yellow bell peppers
- 1 eggplant, about 1/2 pound (a slender eggplant like a Japanese eggplant, not a large globe)
- 1 large zucchini or other summer squash, about 1/2 pound
- 2 medium tomatoes
- 3 cloves garlic, peeled and smashed
- 1 1/2 teaspoons salt
- 2 tablespoons chopped fresh parsley
- 2 ounces provolone cheese, sliced or grated
- 3 tablespoons grated Parmesan cheese
Preheat the oven:
Preheat the oven to 350°F. Place the oven rack in the center position.
Sauté the onions and peppers:
In a large sauté pan heat 2 tablespoons of the olive oil on medium high heat. Add the sliced onions and cook until lightly browned, stirring frequently, about 10 minutes.
Add the sliced bell peppers and continue to cook with the onions until the bell peppers are softened and the onions are well browned, about 5 to 6 minutes more.
When done, transfer the onions and bell peppers into a large gratin pan or casserole dish.
Slice the eggplant, zucchini, and tomato:
While the onions and peppers are cooking, slice the eggplant and zucchini in 1/4-inch thick round slices.
You'll also want to slice the tomato into 1/4-inch thick slices, but depending on how big your tomato is, you may need to cut the tomato in half or in quarters first.
All of the sliced vegetable pieces should be about the same size to make it easier to layer them in an attractive manner.
Layer the sliced vegetables, add the garlic:
Spread the cooked onions and bell peppers in an even layer at the bottom of the gratin dish. Place the mashed garlic on top of the onions and peppers.
Arrange the slices of the eggplant, zucchini, and tomato on top of the cooked onions and peppers, alternating the vegetables, in an attractive pattern, stacking and fanning them across the surface of the dish.
Top with salt, parsley, cheeses, and olive oil:
Sprinkle with salt and parsley. Top with provolone and Parmesan cheeses.
Drizzle the remaining tablespoon of olive oil around the perimeter, where the vegetables meet the side of the dish.
Bake, then broil to finish:
Cover with foil (it helps to grease the underside of the foil with a little olive oil so that the cheese as it melts does not stick to the foil).
Bake for 40 minutes. Remove the foil. Turn on the broiler and broil for 5 minutes or until nicely browned.