Start by preheating the oven to 325 degrees F. Lay out the shelled or slivered pistachios evenly on a baking sheet. Roast for 5 to 10 minutes until fragrant, ensuring they don’t brown (slivered pistachios will require less time, while whole pistachios may need a bit more time). Once done, remove from the oven and allow them to cool slightly.

Next, place the cooled pistachios in the bowl of a food processor or blender. Blend until they transform into a fine powder. If using a blender, utilize a tamper to help keep the nuts in motion.

Continue processing the mixture for an additional 5 to 10 minutes, making sure to scrape down the sides as necessary, until the pistachios reach a smooth and creamy texture. If desired, adding a teaspoon of pistachio oil can aid in achieving a better consistency.

When the butter has reached your preferred smoothness, sprinkle in a pinch of salt (if using) and pulse a couple of times to mix it in. Transfer the finished pistachio butter into a jar or airtight container.

While it’s not necessary to refrigerate your pistachio butter, storing it in the fridge in an airtight jar is recommended for freshness. It will last for about a month, but you can also freeze it for extended storage.