Sift together the flour, one cup of sugar and the cocoa powder in a mixing bowl. Mix in the softened butter with an electric mixer or wooden spoon until smooth.
Transfer dough to an ungreased jelly roll pan or a 15-inch by 11-inch baking sheet. Press the cookie dough into the pan with you hands to form a smooth, even cookie.
Refrigerate the cookie dough in the pan for at least 10-minutes, then cut the dough lengthwise into four strips. Cut the strips crosswise into 32 rectangular sections. Cut each rectangular section on an angle to create 2 cookie wedges from each section.(Makes About 5-Dozen Cookies)
Bake for about 20-minutes, or until the top is dry. Remove the baking sheet to a wire rack and re-cut the cookies while still warm.
Let cool completely, sift the remaining confectioner�s sugar over the top of the cookies. Their flavor improves with time after being stored in an airtight container.