This summer vegetable gratin recipe uses the summer’s bounty of vegetables like summer squash, and zucchini to make a rustic yet simple gratin. It works perfectly when served hot or at room temperature.

From the kitchen of world-renowned chef Alain Ducasse comes this pretty, Provençal-inspired gratin of summer veggies. Those familiar with the cooking of the south of France will notice that his take on tradition leans more toward fancy-pants Ducasse-ian than the rustic, laissez-faire tactic taken by many gratins. Still, you’ll hear no complaints from us. None at all.–Renee Schettler Rossi
LC Fancy and Low-Fat French Cooking?! Note
Fancy and low-fat French cooking? Believe it. Ducasse suggests that rather than sautéing the sliced eggplant, zucchini, and summer squash, you grill or broil it. “The dish then becomes low in fat without any loss of nutritional value,” he explains. He forgot to say there’s no loss of the fancy-pants presentation that’s elegant enough for company, but that’s okay. That’s why we’re here.
☞ Contents
Summer Vegetable Gratin

Equipment
- Mandolin
Ingredients
- 4 tomatoes, preferably actual summer tomatoes from the garden or greenmarket
- 1 small red bell pepper
- 1 small yellow bell pepper
- 1 small green bell pepper
- 1 white onion
- 1 garlic clove
- 4 sprigs basil
- 1 small eggplant
- 1 zucchini
- 1 summer squash
- Olive oil
Directions
- Wash the tomatoes and bell peppers. Cut each tomato crosswise into 6 slices [Editor’s Note: If you’d prefer to save yourself a little fuss, roughly chop the tomatoes rather than slice them.] Peel the bell peppers with a vegetable peeler, remove the stems and all the seeds and the white membranes, and then cut the peppers lengthwise into strips. Peel the onion and cut it into strips. Peel and crush the garlic clove. Place the tomatoes on a plate. Place the bell pepper strips and onion strips and garlic clove together in a bowl.
- Strip the leaves from the basil sprigs and toss the sprigs in the compost or trash. Select the smallest leaves and set them aside in the refrigerator. Cut the large leaves with kitchen scissors and set them aside on a small plate.
- Wash the eggplant, zucchini, and summer squash. Using a mandolin, cut each vegetable lengthwise into long, elegant slices approximately 1/3-inch thick.
- Heat a splash of olive oil in a sauté pan over medium heat. Add the contents of the bowl (the peppers, onion, and garlic) to the pan and toss to coat with oil. Cover and cook, stirring only occasionally, for 10 minutes.
- Uncover the pan, lift the vegetables up with a spatula, and slip the sliced [or diced] tomatoes underneath. Cover and continue to cook for 5 minutes. Then scrape it all back into the bowl, add the chopped basil, and gently toss.
- Wipe out the pan and heat another splash of olive oil in it over medium heat. Sauté the eggplant for 1 to 2 minutes per side. Add salt and freshly ground black pepper and transfer to a plate. Do the same with the zucchini and then the squash.
- Preheat the oven to 350°F (176°C).
- Arrange 1/3 of the eggplant, zucchini, and squash slices side by side and overlapping slightly in a 9-by-13-inch baking dish, alternating the colors. Using a slotted spoon, spread half of the tomato mixture on top, leaving any liquid in the bowl. Add half of the remaining eggplant, zucchini, and squash, arranging the slices neatly. Spread the rest of the tomato mixture on top, again leaving any liquid in the bowl. Finish with a final layer of the remaining eggplant, zucchini, and squash.
- Bake the gratin for 15 minutes. Allow the dish to cool slightly, then sprinkle with the reserved small basil leaves and a generous twist of freshly ground black pepper. The gratin is best served warm. (You can make the gratin hours in advance, let it cool, and then hold it at room temperature. Cover it tightly and reheat it gently in an oven preheated to 325°F.)
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Recipe Testers’ Reviews
This has to be one of the best simple, healthy recipes I have tried in a long time! I don’t think I’ve ever seen a gratin recipe that did not call for cheese, cream, or buttered bread crumbs before, so I was just hoping for okay, but instead I was so impressed by the amount of flavor that developed simply from the vegetables, garlic, and basil. I didn’t use eggplant, so I just increased the amount of zucchini and yellow squash, which I grilled. I used a small stoneware baking dish. While letting this cool on my island prior to dinner, my family decided this would be a great appetizer and started scooping it up with crostini. Some even added cheese. Next thing I knew it was gone. I made this again tonight and let it cool out of sight. It really is wonderful. It’s worth the extra time to cook the veggies first and reduce the amount of liquid before combining them to create such a lovely union.
This recipe surprised me. As I was making it, I was wondering how the family was going to accept it, as it barely had any seasonings and was called “gratin” yet had no cheese on it. Well, once we started eating it, we all loved its beauty on the plate with all of the colors as well as how we could actually distinguish the various vegetables. An absolute perfect addition to a grilled steak with no need for any side carbs.
Flavorful! This recipe is delicious and healthy and, better yet, allows us to take advantage of the summer vegetables at our local farmers markets! When I prepared this, I chose to roast the zucchini, squash, and eggplant. It worked delightfully. The combination of vegetables and just a little salt and pepper and wow…it’s really packed with flavor. The basil adds an extra touch of freshness. I’d suggest dicing the tomatoes instead of slicing. This way, when they cook down, there won’t be any long pieces of tomato skin. Also, I would cook the tomatoes in two batches with the onion and pepper mixture. When assembling, use a slotted spoon to top the layers of eggplant, zucchini and squash with the vegetable mixture in order to leave excess liquid behind. A 9-by-13-inch dish works perfectly, and although this gratin is excellent as is, I could see serving it with a sprinkle of freshly grated Parmesan or using it for a nice vegetarian lasagna. Thumbs up!
This one takes some prep time, but in the end it’s worth it. Next time I would peel the tomatoes instead of the bell peppers. A 9-by-13-inch baking dish was perfect for the amount of veggies I had, but I think this would also make a beautiful presentation in a gratin dish. Since I’m trying to eat a little healthier, I did opt to use the low-fat method of broiling the zucchini and eggplant as suggested. Next time I will also do the squash that way. We ate this as a side dish with steak and it was delicious. Since my daughter doesn’t eat red meat, this became her main dish. She thought it was good, but after tasting it decided to add some grated Parmesan to hers and she liked it that way, too.
Originally published August 22, 2012
If you make this recipe, snap a photo and hashtag it #LeitesCulinaria. We'd love to see your creations on Instagram, Facebook, and Twitter.
Vicki Lionberger
I loved, loved, loved this recipe. It has so much flavor, but it must also be very healthy. The basil has just gotten big enough to harvest in my garden, and in this dish it gives such a huge punch of fresh summer taste. I grilled the vegetables ’til they were mostly done but not black by any means. I used a 9-by-13-inch casserole for the time in the oven and my best olive oil. This is important, as it is a valuable taste in the dish. We loved it and will be making it many times this summer!