SUMMER VEGETABLE GRATIN

Steps:

• Heat oven to 400 degrees and adjust oven rack to upper middle position. Brush the baking pan with 1 teaspoon of the oil. Toss zucchini and yellow squash with 1/2 teaspoon salt in a colander over a bowl and let sit for 30 minutes. Spread on several layers of paper towel to dry. Spread tomato slices on additional layers of paper towel. Let sit for 30 minutes. Heat 2 teaspoons oil in a 10-inch nonstick skillet over medium heat until shimmering. Add onion, cover and cook, stirring occasionally, for 5 to 7 minutes. Uncover and continue cooking until the onion is softened and deep golden brown, about 10 minutes longer. Transfer to a bowl. Combine remaining 1 tablespoon oil, garlic, pepper, and thyme in a small bowl. In a large bowl, toss the zucchini and squash with half of the garlic-oil mixture, then arrange in the prepared baking pan. Evenly arrange the caramelized onions over the squash, then slightly overlap the tomato slices on top of the onions. Spoon remaining garlic-oil mixture over the tomatoes. Bake until the vegetables are tender and the tomato slices starting to brown around the edges, 30 to 35 minutes. Sprinkle with the parmesan and continue to bake until vegetables bubble and cheese is lightly browned, about 10 minutes longer. Let sit for about 10 minutes and sprinkle with the basil before serving.