2 tablespoons olive oil
1 medium onion, chopped
3 garlic cloves, minced
1 and 1/2 teaspoons dried thyme
1 can (28 ounces) whole tomatoes
1 can (28 ounces) crushed tomatoes
2 pounds ravioli
1 and 1/2 cups shredded mozzarella
1/2 cup grated Parmesan
Preheat the oven to 425 degrees. Heat the oil in a large saucepan over medium heat. Add the onion and garlic, and season with salt and pepper; cook, stirring occasionally, until softened, about 5 minutes. Add the thyme and tomatoes. Bring to a boil, reduce heat, and simmer, breaking up the tomatoes with a spoon, until the sauce is thickened, 20 to 25 minutes.
Meanwhile, cook ravioli in a large pot of boiling salted water just until they float to the top (the pasta will continue to cook in the oven). Drain the pasta; return to the pot. Toss the sauce with the pasta. Pour the pasta into a large gratin dish or 9-by-13-inch baking dish, and sprinkle with the cheeses. Bake until golden, 20 to 25 minutes. Cool slightly before serving.