Ingredients

• Ingredients for basic butter cookies
• 1/2 cup Dutch-process unsweetened cocoa powder
• 1/2 teaspoon baking soda
• 10 1/2 oz fine-quality bittersweet chocolate (not unsweetened), melted and cooled
• Garnish: salted roasted pistachios, finely ground; Demerara sugar

Instructions

1. Follow recipe for basic butter cookies, mixing in cocoa, baking soda, and melted chocolate after adding flour (dough will be stiff). Form dough into a 14-inch log (2 inches in diameter) on a sheet of plastic wrap and roll up dough. (Dough will be hard to slice and may crumble.)
2. If garnishing, roll edges of each slice first in pistachios and then in Demerara sugar.