Preheat the oven to 350°F (175°C). Spread the pistachios on a baking sheet and toast for 5-7 minutes, or until fragrant. Let cool slightly.

Add the toasted pistachios to a food processor. Blend for 10-15 minutes, stopping occasionally to scrape down the sides, until a thick paste forms.

Add the powdered sugar and 2 tablespoons of oil. Blend until smooth. Add more oil if needed to reach your desired consistency.

Transfer the paste to an airtight container and store in the fridge for up to 2 weeks.