Cream the butter and sugar. Stir in egg yolks and whole egg; blend. In a separate bowl, sift all dry ingredients except the confectioners' sugar; add to creamed mixture, alternating with buttermilk. Stir to mix all ingredients. Cook by dropping spoonsfuls of dough into 190ºC deep fat. Fry a few at a time, to keep fat temperature constant. Turn to brown on all sides. Drain on paper towels; sprinkle with confectioners' sugar.