In a medium bowl, mix the sugar and butter together. Stir in the eggs and vanilla. Then mix in the flour, cocoa, and walnuts. Preheat the waffle iron.
Drop dough by heaping tablespoons onto the center of the waffle iron. Close the lid and cook for 1 1/2 minutes. It may take more or less time depending on the individual waffle iron. Cut the pieces into cookies while still warm. Dust with confectioners' sugar if desired.
