Provençal Tian (Eggplant, Zucchini, Squash, and Tomato Casserole) Recipe

This handsome cousin of ratatouille concentrates the flavors of late summer produce.

Top down view of a tian in an earthenware baking dish.
Meet ratatouille's beautiful cousin: the tian.

Serious Eats / Daniel Gritzer

Why It Works

  • Pre-cooking each vegetable in a skillet removes excess moisture and browns the slices, making the final dish much more flavorful.
  • Cutting each vegetable between 1/8 and 1/4 inch thick delivers perfect slices. Any thinner, and the slices shrink away to nothing during cooking; any thicker, and the tian seems clunky and lacks elegance.

You know the final scene of the 2007 Disney movie Ratatouille, when the rat cooks up an amazingly inspired reinterpretation of a classic ratatouille, transforming the humble summer vegetable stew into a gorgeous layered construction that melts a bitter restaurant critic's heart? Wasn't it wonderful? And didn't it then inspire an endless rash of internet recipes, each attempting to re-create the movie's "ratatouille" for everyone to make at home?

Well, I have an issue with all of that, because as far as I'm concerned, the dish in the movie isn't ratatouille, no matter how you slice it—or, actually, specifically because of how you slice it and then cook it.

As the story goes, Thomas Keller, who consulted on the film, offered his fancy layered "ratatouille" recipe as the pièce de résistance for that final scene; he called it a byaldi. Keller's byaldi, meanwhile, can be traced back to the French chef Michel Guérard, one of the founders of nouvelle cuisine, who named it after a Turkish stuffed eggplant dish.

Here's the problem: That upgraded ratatouille traveled an unnecessarily convoluted path through the hands of two famous chefs and one Disney movie, because it already existed in Provence, sitting right alongside ratatouille on the dinner table. It's been made there for generations, and any restaurant critic worth his salt would have recognized it for what it was right away—not ratatouille, but a tian.

Technically, a tian is any casserole cooked in an earthenware vessel by the same name, but these days it almost always refers to some kind of layered vegetable dish that's gratinéed (browned on top) in the oven. Zucchini and other squash are very common in tians, as are eggplant and tomato. (Notice the overlap with ratatouille ingredients...but, still, doesn't make it ratatouille.) And they're often made very much like you see in the movie, with some kind of sauce in the casserole and raw, thinly sliced vegetables either tossed in the sauce or layered on top, then baked until the vegetables are tender.

But my problem with the dish isn't just a semantic one. I also have issues with the overall method of cooking the dish, because it almost always ends up with the vegetables tasting bland. That shouldn't be much of a surprise—what else is going to happen when watery vegetables are crowded together in a dish and then baked in a steamy cloud of each other's moisture?

So, not only do I want to restore this dish to its proper name—a tian—I also want to improve how this particular tian tastes, making sure that the flavors end up concentrated and intense, not watery and bland.

Uniform slices of eggplant, zucchini, and yellow summer squash, stacked so that they're in the same shape they were before being cut.

Serious Eats / Daniel Gritzer

The obvious fix is to pre-cook each vegetable individually to get rid of some of the excess moisture before layering them together. Plus, pre-cooking means we can better develop their flavors by browning each piece, which is almost impossible when they're steaming away in the oven.

I played with a couple of ways to do that. I was sure the easiest would be to toss each sliced vegetable with oil, spread them in a single layer on baking sheets, and roast them in the oven, but that didn't work well at all: When sliced thinly, vegetables like squash and eggplant dehydrate in the oven long before they brown.

I tried pre-salting the eggplant and squashes to drive off some excess moisture before putting them in the oven. But those thin slices absorb way too much salt, and, since they're the bulk of the final dish, it ends up horribly salty.

Overhead shot of zucchini slices being browned in a skillet.

Serious Eats / Daniel Gritzer

Ultimately, I found that the best method was to sauté each sliced vegetable in a very hot skillet, working in batches small enough to guarantee that they'd brown before they risked overcooking and turning to mush. I also found that the ideal slice thickness is somewhere between one-eighth and one-quarter of an inch—any thinner, and the slices shrink to almost nothing as they cook, making them incredibly difficult to work with later.

It takes a little time to do this, but not too much, and the flavor improvement is well worth it. As each batch finished, I transferred it to a baking sheet, spreading the vegetables in an even layer to cool. As you can see, the fastidious side of me took over—I couldn't resist the urge to re-stack each vegetable after it had cooled, which actually made them really easy to work with later.

A round earthenware casserole. The bottom of the vessel is covered in a thin layer of tomato sauce.

Serious Eats / Daniel Gritzer

With the vegetables cooked, I whipped up a quick tomato sauce, then spooned it into the bottom of an earthenware casserole. Mine has about a two-quart capacity, but there's some flexibility on the necessary volume and shape of the baking vessel. Just arrange the vegetables in a way that works, packing them more tightly if the dish is smaller and spacing them apart more if it's bigger.

The tian, assembled but without the last addition of tomato sauce. The slices of eggplant, zucchini, and squash have been shingled in a spiral pattern, starting with the outermost ring and working inward.

Serious Eats / Daniel Gritzer

If your dish is round, a circular pattern, like what I used here, works well; if it's rectangular, you may want to do rows instead. Then I spooned a little more sauce on top, popped the dish in a hot oven, and cooked it until it was heated through. I didn't worry too much about browning the top of the casserole here, since I'd already browned all my vegetable slices beforehand.

The finished tian, fresh from the oven.

Serious Eats / Daniel Gritzer

Because the vegetables had a head start on cooking, they reduced and intensified in flavor in the oven, becoming creamy and getting a nice balance of bright flavors and sweetness from the browning. If I were to describe the result, I'd say it was like the love child of Italian eggplant parm and, well, ratatouille. That's a far better background story, anyway.

August 2015

Recipe Facts



Active: 90 mins
Total: 105 mins
Serves: 4 servings

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  • About 1/2 cup extra-virgin olive oil, divided

  • 3/4 pound zucchini (about 2 medium), ends trimmed and thinly sliced crosswise between 1/8 and 1/4 inch thick

  • Kosher salt

  • 3/4 pound summer squash (about 2 medium), ends trimmed and thinly sliced crosswise between 1/8 and 1/4 inch thick

  • 3/4 pound Japanese eggplant (about 2), ends trimmed and thinly sliced crosswise between 1/8 and 1/4 inch thick

  • 3 medium cloves garlic, crushed

  • 1/4 cup chopped yellow onion (from 1 small onion)

  • 1 (28-ounce) can whole peeled tomatoes, crushed by hand

  • 1 teaspoon chopped fresh oregano or marjoram leaves

  • Freshly ground black pepper


  1. In a large skillet, heat 2 tablespoons olive oil over high heat until shimmering. Working in batches and being sure not to crowd the pan, add zucchini, season with salt, and cook, turning, until just tender and browned in spots, about 4 minutes per batch. Add more oil as needed to prevent pan from drying out, and adjust heat as needed throughout to maintain a very hot, but not heavily smoking, pan. Transfer each batch to a baking sheet and spread in an even layer to cool, then transfer cooled slices to a second baking sheet or plate. Repeat with remaining zucchini, squash, and eggplant until all vegetables are lightly browned.

    Browned zucchini, squash, and eggplant slices arranged in neat stacks on a rimmed baking sheet..

    Serious Eats / Daniel Gritzer

  2. In a medium saucepan, heat 2 tablespoons olive oil over medium heat until shimmering. Add garlic and onion and cook, stirring, until softened, about 4 minutes. Add crushed tomatoes, bring to a simmer, and cook, stirring and adjusting heat to maintain simmer, for 15 minutes. Blend to a smooth purée with a hand blender or in a countertop blender, then add marjoram or oregano. Season with salt and pepper.

  3. In an earthenware, ceramic, or glass baking dish, spoon just enough sauce to cover bottom of dish in a thin, even layer. Arrange sautéed vegetable slices in an alternating layered pattern (see notes) on top of sauce until entire dish is filled. Spoon a thin layer of sauce on top of vegetables; reserve remaining sauce for another use.

    Author spooning tomato sauce over the browned vegetable slices.

    Serious Eats / Daniel Gritzer

  4. When ready to bake, preheat oven to 450°F (230°C). Bake until tian is fully heated through and lightly browned on top, about 15 minutes. Serve.

Special Equipment

Earthenware, ceramic, or glass casserole or baking dish (about 2-quart capacity; see note); rimmed baking sheets; blender or immersion blender; mandoline slicer


The exact size and shape of the baking dish are flexible. The vegetables should be layered more tightly in a smaller dish and spaced more widely apart in a larger one. In round dishes, it's best to layer the vegetables in a circular pattern; in rectangular dishes, they should be layered in rows.

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Nutrition Facts (per serving)
344 Calories
28g Fat
23g Carbs
5g Protein
Show Full Nutrition Label Hide Full Nutrition Label
Nutrition Facts
Servings: 4
Amount per serving
Calories 344
% Daily Value*
Total Fat 28g 36%
Saturated Fat 4g 20%
Cholesterol 0mg 0%
Sodium 487mg 21%
Total Carbohydrate 23g 8%
Dietary Fiber 7g 25%
Total Sugars 12g
Protein 5g
Vitamin C 45mg 227%
Calcium 74mg 6%
Iron 2mg 9%
Potassium 999mg 21%
*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.
(Nutrition information is calculated using an ingredient database and should be considered an estimate.)