Remove all the pulp from pumpkin seeds. Wash them throughly using a colander. Let them dry overnight in a single layer.
Preheat oven to 350°F (177ºC).
In a small bowl combine pumpkin seeds, olive oil, salt, garlic powder, paprika (if using), and black pepper.
Prepare a sheet pan with parchment paper. Evenly spread the seasoned pumpkin seeds on the sheet pan.
Bake until the seeds are toasted and crunchy, about 12 to 15 minutes. Stir every 5 minutes for even toasting, and check for doneness with each stir by tasting a seed for crunchiness.
Transfer the roasted pumpkin seeds to a bowl to cool down.