tablespoons (1 stick) unsalted butter, room temperature
cup all-purpose flour (spooned and leveled)
cup confectioners' sugar
tablespoons unsweetened cocoa powder
Prep time: 15 minutes Total time: 1 hour, 15 minutes Preheat oven to 300. With an electric mixer, beat butter until creamy. Add flour, sugar, and cocoa; mix just until combined. (Chill dough in the refrigerator 10 minutes if it is too soft to handle.) Pat dough into an 8-inch round cake pan; press edges down with the tines of a floured fork. Bake until firm, 30 minutes. Immediately score into 8 wedges; cool completely. Turn out of pan; break wedges apart. Shortbread can be stored in an airtight container at room temperature for up to 3 days.