Set two racks in the middle of the oven. Preheat to 375 degrees.
In a food processor, or bowl of an electric mixer, thoroughly mix the flour, cocoa, baking soda and powder, salt, and sugar. While pulsing, or on low speed, add the butter, and then the egg. Continue processing or mixing until dough comes together in a mass.
Take rounded teaspoons of batter and place on a parchment paper-lined baking sheet approximately 2 inches apart. With moistened hands, slightly flatten the dough. Bake for 9 minutes, rotating once for even baking. Set baking sheets on a rack to cool.