1/4 cup butter
1 pound lean ground beef
1/4 cup chopped onion
1 (8 ounce) package cream cheese, softened
1 (8 ounce) container sour cream
1 (8 ounce) package shredded mozzarella cheese
1 (8 ounce) package shredded Cheddar cheese
Preheat oven to 375 degrees F (190 degrees C).
In a large mixing bowl, cream together the butter and ground beef. Mix in the onion, cream cheese, sour cream and mozzarella cheese. Mix in the sifted ingredients, then pour mixture into a 9x13 inch baking dish.
Bake in the preheated oven for 20 minutes, until pizza is bubbly and golden brown.