Combine all the base ingredients in a bowl, gently tossing until evenly combined.
Spoon the mixture into a greased mini muffin tin (about 1-2 Tbsp), press down. Bake at 350F for 8-12 minutes.
Top each with 1-2 Tbsp of Marinara sauce, pepperoni slice, 1-2 Tbsp mozzarella, then place under broiler for 5 minutes or until the cheese is melted and golden.