Prepare this ahead of time, then when your guests arrive, pop the pan in the oven and spend time with your guests! Also works great with almost any kind of pasta: layered like lasagna, stuffed in manicotti or big seashells, mixed willy-nilly with linguine or elbow macaroni. So many choices! Double the recipe, make two pans, freeze one and cook the other right away.
This is a kid pleaser-very cheesy and topped with pepperoni. It makes 2 large (9x13) casseroles or 4 small ones; I often divide it in fourths and freeze 3. This originally came from TOH's Quick Cooking.