parmesan cheese, onion, salt and oregano. Shape into a loaf and place in a greased 9 x 5 x 3 loaf pan. Bake at 350 for 1 1/4 hours or until no pink remains; drain. Spoon pizza sauce over loaf and top with cheese slices. Return ot the oven for 10 minutes or until the cheese is melted. Meanwhile, if desired, saute green pepper and mushrooms in butter; arrange on top of meat loaf.