Chocolate Shortbread (Cookies)

Sift flour, 1 cup sugar, and the cocoa into mixer bowl. Mix in butter with electric mixer or wooden spoon until smooth.

Transfer dough to ungreased jelly-roll pan, 15x11 inches, and press with fingertips until even. Refrigerate 10 minutes.

Heat oven to 325F.

Cut dough lengthwise into 4 strips, then cut crosswise to make 32 rectangles. Cut each rectangle diagonally into 2 triangles. Prick each triangle twice with a fork.

Bake until top feels dry, about 20 minutes. Remove pan to wire rack and recut cookies while warm. Let cool completely. Sift remaining sugar over top. Flavor improves when stored in airtight container.