Preheat oven to 300º F. Line a baking sheet with parchment.
In a medium saucepan or microwaveable bowl, combine all ingredients together except the pumpkin seeds and heat, stirring occasionally, just until sugar dissolves and butter melts.
Add the pumpkin seeds and toss until well coated.
Spread pumpkin seeds with any excess coating out in a single layer on the sheet pan and roast 25-30 minutes, turning and tossing mixture once or twice while roasting. Continue to roast until the seeds are dry and golden brown.
Serve seeds warm or store up to 1 week in a covered container. Seeds may be reheated in the oven at 200°F for 10 minutes before serving. For best results, do not microwave to re-heat.
Grease tongs when tossing the seeds to keep the coating from sticking to the tongs.