Thomas Keller's Summer Vegetable Gratin

Thomas Keller’s version of a cheese less gratin is just as satisfying.

Thomas Keller’s Squash Vegetable Gratin

A not so cheesy way to make vegetable gratin! This is a healthy and low fat recipe of the classic vegetable gratin we’re used to seeing. I like this one because of its simplicity and meatiness the vegetables mimic so well. Making healthy and low calorie meals doesn’t have to be boring or taste bland; the sweetness of the tomatoes are what makes this dish shine. Vegetarian foods also get a bad reputation for tasting like cardboard, well guess what; this is one vegetarian recipe you’ll fall in love with! This recipe is taken from Thomas Keller’s Ad Hoc.

Thomas Keller’s vegetable gratin

thomas keller vegetable gratin
  • Prep Time: 10 minutes
  • Cook Time: 90 minutes
  • Total Time: 100 minutes
  • Category: Side
  • Cuisine: Vegetarian, Vegan


  • 23 roma tomatoes (sliced into 2-inch slices)
  • 1 medium yellow squash (ends trimmed and cut into 2-inch slices)
  • 1 medium zucchini (ends trimmed and cut into 2-inch slices)
  • 1 inch Japanese or other narrow eggplant (ends trimmed and cut into 2-inch slices)
  • canola oil
  • 2 1/2 cups onions (coarsely chopped)
  • 2 cloves garlic (finely grated)
  • kosher salt
  • 1 tablespoon thyme (plus 1 additional teaspoon )
  • 1/4 cup extra virgin olive oil (plus more for drizzling)
  • freshly ground pepper
  • 1/2 cup freshly grated Parmigiano-Reggiano
  • 1/2 cup dried bread crumbs


  1. Preheat the oven to 350°F. Set a cooling rack on a baking sheet. Heat about 2 tbsp canola oil in a large pan over medium heat. Add onions and garlic, and season with salt. Lower the heat to medium-low and cook onions until translucent but without browning, for about 20 minutes. Stir in 1 tbsp of the thyme.
  2. Combine the yellow squash, zucchini, and eggplant in a large bowl, toss with the olive oil, and season with salt.
  3. Drizzle the slices of tomatoes with olive oil and season with salt. Combine the Parmesan, bread crumbs, and remaining 1 tsp thyme in a small bowl.
  4. Spread the onion mixture in the bottom of a 13 1/2-by-9 1/2-inch gratin dish or 13-inch round shallow baking dish. Layer the vegetables in the dish, working on the diagonal. Arrange a layer of overlapping slices of one-third of the zucchini around the outside edge of the dish. Sprinkle 2 to 3 tbsp of the cheese mixture over the top.
  5. Make a row of overlapping slices of yellow squash slightly overlapping the zucchini, and sprinkle 2 to 3 tbsp of the cheese mixture over the top.
  6. Make a third row with overlapping slices of tomatoes, slightly overlapping the zucchini, and sprinkle with cheese mixture. Do the same with the eggplant and continue making overlapping rows of the remaining vegetables, and sprinkle the top with any remaining cheese mixture and a light sprinkling of salt.
  7. Bake for 1 to 1 1/2 hours until the vegetables are completely tender and offer no resistance when pierced with a knife. Remove from the oven and let rest for 10 minutes. Turn on the broiler. Just before serving, place the gratin under the broiler to brown the top.
Recipe Card powered byTasty Recipes

Pickled Plum is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to