Cook macaroni according to package directions; drain.
In a bowl, combine the egg, milk and 1/4 cup cheese. Stir in macaroni. Transfer to a greased 3-cup baking dish. In a skillet, cook pork and onion over medium heat until meat is no longer pink; drain. Stir in tomato sauce and cinnamon.
Pour over macaroni mixture. Sprinkle with remaining cheese. Cover and bake at 375° for 20 minutes. Uncover; bake 12-16 minutes longer or until bubbly and heated through.