Roast them! It's an easy recipe. Scoop out the seeds of the pumpkin with a large spoon and put them in a medium or large bowl of cold water and make sure they don't have bits of pumpkin strings attached to them. Put them on a baking sheet, drizzle some olive oil, sprinkle salt and pepper, and dry in a medium/low oven (around 300°F) until dried and golden. Let them cool completely and store them in an airtight container.