Arrange pumpkin seeds in an even layer on a rimmed baking sheet. Roast in the oven for 12 minutes, stirring once, or until fragrant and beginning to turn lightly browned.
Allow the seeds too cool to the touch.
Transfer the seeds to the bowl of a food processor. Process until smooth, scraping down the sides of the bowl as needed. The seeds will become crumbly, then start to lump together, then turn into a smooth butter. This should take 15-20 minutes. If your food processor becomes too hot or overworked, turn it off for 20-30 minutes and then continue.
Add salt and any other additional flavorings, and pulse until incorporated.
Transfer to a jar or other sealed container and store in a cool, dark place. To extend the shelf life, refrigerate until ready to use.
Tips for customizing
Add maple syrup or honey to taste
Flavor with cinnamon, cardamom, chili powder, or curry powder
Add vanilla extract or vanilla powder
If you want it to be even easier to spread, add a little neutral oil (such as canola, avocado, or coconut if you don’t mind the taste)