- 1 cup all-purpose flour
- 1 cup old-fashioned oats
- 1 cup raw pistachios
- 3/4 teaspoon kosher salt
- 1/2 teaspoon baking soda
- 1 cup (2 sticks) unsalted butter, room temperature
- 1/3 cup granulated sugar
- 1/4 cup powdered sugar
- Pulse flour, oats, pistachios, salt, and baking soda in a food processor to combine (small pieces of oats and pistachio should still be visible).
- Using an electric mixer on medium-high speed, beat butter, granulated sugar, and powdered sugar in a medium bowl to create air pockets in butter, about 5 minutes; mixture will look light and fluffy. Reduce speed to low and add dry ingredients, mixing just until blended. Divide dough between 2 sheets of plastic wrap or parchment paper and shape into about 1 1/2″-diameter logs. Chill until firm, at least 1 hour. (The colder your dough, the easier it will be to cut into even slices.)
- Place racks in lower and upper thirds of oven; preheat to 350°. Using a serrated knife, slice logs into 1/4″-thick rounds and place on parchment-lined baking sheets, spacing about 1/2″ apart. Bake, rotating baking sheets once, until cookies are golden brown around the edges, 10–12 minutes. Transfer to wire racks; let cool.
- Do ahead: Keep dough chilled up to 5 days, or freeze up to 1 month.