1/2 c. finely chopped onion
1 c. shredded Mozzarella cheese
Dash of Worcestershire sauce
1/2 c. Parmesan cheese
1 c. Hellmann's real mayonnaise, no substitute

Mix in bowl and cover. Refrigerate 1 or more hours. Spread on cocktail rye or pumpernickel bread making open face sandwiches. Place on cookie sheet. Bake at 400 degrees until cheese melts. Serve immediately.