1 cup margarine, softened
1 egg yolk
2 (4 ounce) packages cream cheese
1 1/2 teaspoons baking powder
2 cups milk
6 (1 ounce) squares American cheese
4 eggs
1 cup shredded mozzarella cheese
Preheat oven to 400 degrees F (200 degrees C).
In a large bowl, combine margarine, egg yolk, cream cheese, baking powder, milk, and cheese. Mix well. Transfer mixture into baking dish.
Bake in preheated oven for 12 minutes, or until bubbly and golden.