Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper.
If using fresh pumpkin seeds, separate them from the pumpkin pulp and rinse them thoroughly.
Pat the pumpkin seeds very dry with a clean kitchen towel or paper towels. Removing excess moisture helps them become crisp.
In a small bowl, combine the granulated sugar, cinnamon, and salt.
Stir the vanilla extract into the melted butter.
Place the dry pumpkin seeds in a large mixing bowl and pour the butter mixture over them. Toss until the seeds are evenly coated.
Sprinkle the cinnamon-sugar mixture over the pumpkin seeds and toss again until the seasoning is distributed evenly.
Spread the seasoned pumpkin seeds across the prepared baking sheet in a single layer.
Bake for 15–20 minutes, stirring once or twice during baking, until the seeds are lightly golden and toasted.
Remove from the oven and let the pumpkin seeds cool completely. They will become crunchier as they cool.
Serve immediately or store in an airtight container once completely cooled.