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.