Preheat oven to 375˚F. Line a rimmed baking sheet with parchment paper or a silicone mat.
Add butter, salt, cinnamon, garlic powder, cayenne pepper, and black pepper to a small bowl. Stir to combine.
Add pumpkin seeds to a medium bowl with the seasoned melted butter. Toss to coat evenly.
Spread seeds on the prepared baking sheet in an even layer, making sure no seeds overlap each other.
Bake for 25 to 35 minutes, until seeds are golden, stirring halfway through. Remove from oven and cool for a couple of minutes before enjoying.