Preheat the oven to 300 degrees F. Line a baking sheet with parchment paper and spray with nonstick cooking spray.
In a small bowl, combine the sugar, cinnamon, allspice, cumin and cayenne. In a large bowl, beat the egg white until frothy. Stir in the pumpkin seeds, then add the sugar mixture and toss until the seeds are completely coated.
Spread the seeds out on the prepared baking sheet. Bake until crispy, 20 to 25 minutes. Let cool completely. Store in an airtight container.