Preheat oven to 375*. Spray cupcake pan(with cooking spray and set aside. Open tube of crescent rolls and separate into its triangles. At the wide end of each triangle, place 3 slices of pepperoni, a cube of mozzarella, and drizzle about 2 teaspoons of marinara over the top. Fold the crescent triangles securely around their stuffing, and place in cupcake well. Bake for 10-14 minutes, or until golden brown and dough is cooked through. Remove from oven, and let sit for 3-4 minutes. Remove from pan and arrange on a serving platter. Serve with additional heated marinara sauce.