Ingredients
1 cup all-purpose flour
2 tablespoons cocoa powder
7 tablespoons confectioners' sugar
1/2 cupn (1 stick) unsalted butter, cut into small pieces and chilled
1 large egg yolk, lightly beaten
1-2 tablespoons ice water
Preparation
Place flour, cocoa powder, and confectioners’ sugar in the bowl of a food processor; pulse to combine. Add butter; pulse until mixture resembles coarse meal.
With motor running, add egg yolk, then 1 to 2 tablespoons ice water; process just until dough begins to come together.
Shape dough into disk; wrap in plastic, and chill at least 1 hour.