Cook spaghetti in large amount of boiling water 10-12 minutes; drain. In large bowl, combine spaghetti and butter; add eggs and Parmesan. Form mixture into a crust in a greased 10 pie pan. Spread with cottage cheese. Cook meat , onion, green pepper until meat is browned and veggies are tender. Drain off fat. Stir in sauce and tomato paste. Heat through.
Turn meat mix into spaghetii crust. Cover edges with foil and bake at 350 for 20 minutes. Sprinkle with mozzarella and bake about 5 minutes more or until cheese is melted.