Preheat oven to 425 degrees F (220 degrees C). Spray 10 muffin cups with cooking spray.
Press biscuits, one at a time, between hands to flatten. Place each flattened biscuit in a muffin cup; press into bottom and up sides of muffin cup. Set aside for biscuit to settle and slightly rise, about 5 minutes. Lightly press biscuits into cups as needed.
Spoon 1 tablespoon pizza sauce into each biscuit; top each with 1 slice pepperoni and 1 tablespoon mozzarella cheese.
Bake in the preheated oven until biscuit is lightly browned and cheese is melted, about 10 minutes. Remove each pizza from tin and place on a cooling rack, about 5 minutes.
