Preheat your oven to 400°F. Line a baking sheet with parchment paper and lightly spray it with cooking spray.
In a mixing bowl, combine the shredded mozzarella and cheddar cheeses, Italian seasoning, garlic powder, and black pepper. Mix well until all ingredients are evenly distributed.
Using a tablespoon, drop heaping spoonfuls of the cheese mixture onto the prepared baking sheet, leaving about 2 inches of space between each mound. Flatten each mound slightly with the back of the spoon.
Top each cheese mound with a slice of pepperoni.
Bake in the preheated oven for 8-10 minutes or until the edges are golden brown and the cheese is bubbly.
Remove from the oven and let cool for 5 minutes before transferring to a wire rack to cool completely.
Serve warm or at room temperature.