Step 1

Get ready. Position a rack in the center of the oven and heat the oven to 350°F. Spread the pistachios on a large rimmed baking sheet.

Step 2

Roast the pistachios. When the oven is hot, set the baking sheet on the middle rack for 5 minutes. Give the pistachios a good stir and return to the oven. Roast until the pistachios are fragrant and slightly golden, 3 to 5 minutes more.

Step 3

Cool, then blend. Remove from the oven and let cool for just about 10 minutes. While the pistachios are warm, transfer them ot the bowl of a food processor fitted with a blade. Blend until they turn from flour-like crumbs to a smooth, creamy, buttery mixture. This may take some time, and you do need to stop occasionally to scrape the sides and give the food processor a break.

Step 4

Season. Taste and adjust salt to your liking, blending briefly to distribute the seasoning.

Step 5

Store. Let the pistachio butter cool to room temperature before transferring to a sealable container. Store at room temperature for up to 1 week or in the fridge for up to 4 weeks.