1. In a food processor, process butter, confectioners' sugar, and salt until smooth. Add flour and pulse until a dough forms. Stir in pistachios. Divide dough into 2 disks; wrap each in plastic and refrigerate until firm, 1 hour.

2. Preheat oven to 350 degrees. Working with one disk at a time, roll out on a lightly floured work surface to 1/4 inch thick. Using a 2-inch round fluted cutter, cut out wreaths. Using a 3/4-inch round cutter, cut out centers of wreaths. Reroll scraps. Transfer to parchment-lined baking sheets. Freeze until firm, 15 minutes. Bake until cookies are set and barely golden at edges, 10 to 12 minutes. Transfer cookies on sheets to wire racks; let cool completely. Cookies can be stored in an airtight container at room temperature up to 1 week.