2Mix sour cream, ricotta cheese, 3/4 cup mozzarella cheese, pepperoni, and soup mix together in a large bowl. Spread in a 9-inch baking pan. Sprinkle remaining 1/4 cup mozzarella cheese on top.
3Bake in the preheated oven until center is heated through and mozzarella cheese is melted, about 30 minutes.