In a bowl (preferably metal) stir together flour, granulated sugar, cocoa, baking powder, salt, and blend in butter. Stir in egg and vanilla until mixture is blended. NOTE: (Some people add ¼ cup mini chocolate chips to make richer, I did not).
Spread dough in a thin layer in bowl and freeze 10 minutes, or until firm.
Preheat oven to 400°F and lightly grease 2 baking sheets.
Put 4 tablespoons confectioners' sugar in a small bowl and dust hands with additional. Roll each piece of dough into a ball (small – gumball size) and then in confectioners' sugar in bowl. Arrange balls 2 inches apart on baking sheets, bake 8 to 10 minutes, or until cookies are just set. Cool cookies on racks.