1 pound pasta (penne, ziti, or rigatoni), cooked until almost tender and then drained
1 26-ounce jar of your favorite tomato pasta sauce (2 to 3 cups)
1 pound cooked ground beef or sausage (optional)
About 2 cups shredded mozzarella cheese
1/4 cup grated Parmesan cheese
Preheat oven to 400 degrees. Combine the cooked and drained pasta with the tomato sauce (and meat, if desired). Spread half of the pasta mixture in a 9 by 13-inch baking dish that has been sprayed with cooking spray. Sprinkle with half of the mozzarella and half of the Parmesan. Spread the remaining pasta mixture in the dish and then sprinkle with the remaining cheeses. Bake until the cheeses turn golden brown, about 20 minutes. Let cool 5 minutes before serving.