1 lb. ground beef
6 oz. can tomato paste
1 tbsp. Worcestershire sauce
1/2 tsp. oregano
1/4 c. butter, softened
1 1/2 c. shredded Mozzarella cheese
1/2 c. chopped onion
1 loaf Italian bread, cut in half lengthwise

Brown beef and onion in a frying pan and drain. Stir in tomato paste, Worcestershire sauce and oregano. Place bread cut side up on a large baking sheet. Spread with butter, toast under broiler until golden. Spread meat mixture on tops. Sprinkle on cheese. Broil 4-6 minutes or until cheese is slightly melted. Slice and serve.