Preheat oven to 425 degrees F.
Arrange pepperoni slices in a single layer on a baking sheet and bake for 8 to 10 minutes.
Remove pan from oven and soak up the excess grease with paper towels. Return pan to oven and bake additional 2 to 4 minutes, until pepperoni slices are very crispy.
Garnish with freshly shaved Parmesan cheese and serve!