How to Make It
Heat oven to 300°F. Spread the pumpkin seeds on a rimmed baking sheet and bake until dry throughout, 50 to 60 minutes.
Increase oven temperature to 350°F. In a large bowl, toss the pumpkin seeds with the butter, sugar, salt, and cinnamon. Return the seeds to the baking sheet and toast, tossing occasionally, until golden brown, 10 to 15 minutes.
To remove seeds from the pumpkin, scoop out the seeds with a spoon or by using your fingers. Then discard any bits of stringy pulp before placing pumpkin seeds into a colander and giving them a good rinse.
In a pinch, you can toast pumpkin seeds in the microwave by heating them in a single layer on a glass baking dish or pie plate. Microwave pumpkin seeds for about 2 minutes and stir. Heat again for 2 to 3 minutes, stirring after each minute, until the seeds are lightly browned and crunchy.