Preheat oven to 350°F. In a large bowl, combine evaporated milk, bread crumbs, onion, salt, Italian seasoning, and pepper. Add ground meat; mix well. Lightly press mixture evenly onto the bottom and up the side of an ungreased 9-inch pie plate. Bake, uncovered, about 30 minutes or until done (160°F). Carefully tilt dish and drain off fat.
Meanwhile, cook spaghetti according to package directions; drain. Return to pan. Stir in butter until melted. Stir in egg and Parmesan cheese until spaghetti is coated.
Spread half of the pizza sauce over meat mixture. Top with 1/2 cup of the mozzarella cheese and the spaghetti mixture. Top with the remaining pizza sauce and the remaining 1/2 cup mozzarella cheese.
Bake, uncovered, about 20 minutes or until heated through. (If necessary, cover edges of meat mixture with foil to prevent over browning.) Let stand for 15 minutes before serving.