Food & Cooking Recipes Main Dish Recipes Casserole Recipes Potato, Zucchini, and Tomato Gratin 3.5 (224) 2 Reviews By Martha Stewart Test Kitchen Martha Stewart Test Kitchen The recipes developed by our test kitchen team have undergone a rigorous process of development and testing, ensuring that every element is optimal, from ingredient amounts to method and cooking time. This process includes triple-testing recipes to ensure they meet our high standards. The many stellar cooks and food editors who have been part of our team include Sarah Carey, Lucinda Scala Quinn, Jennifer Aaronson, Shira Bocar, Anna Kovel, Greg Lofts, Riley Wofford, Lauren Tyrell, and Lindsay Leopold. Editorial Guidelines Updated on January 21, 2021 Print Rate It Share Share Tweet Pin Email Photo: Mikkel Vang Servings: 4 Drizzle fruity extra-virgin olive oil over thin slices of potato, zucchini, and tomato for a low-fat summery potato gratin. A sprinkling of cheese provides nutty flavor. Ingredients 5 teaspoons extra-virgin olive oil 2 garlic cloves, minced 1 pound Yukon gold potatoes, peeled 1 medium zucchini (about 8 ounces) 2 vine-ripened or other ripe tomatoes (about ¾ pound), sliced into ¼-inch rounds ¼ teaspoon coarse salt Freshly ground pepper 1 teaspoon finely chopped fresh thyme 2 ounces finely grated Cantal or cheddar cheese Directions Preheat oven to 375 degrees with rack in upper third. Coat a 9-by-13-inch gratin dish with 1 teaspoon oil, and sprinkle with garlic. Using a mandoline or a very sharp knife, slice potatoes and zucchini as thinly as possible into rounds. Arrange potatoes, zucchini, and tomatoes in overlapping layers around prepared dish, and sprinkle with the salt and pepper. Drizzle with remaining 4 teaspoons oil, and sprinkle with thyme and cheese. Cover with foil; bake until potatoes are tender, 35 to 45 minutes. Remove foil; continue baking until top is golden brown, about 25 minutes more. Remove from oven; and serve immediately. Rate it Print