Mix the flour, caraway seeds and sugar together. Work in the butter with the finger tips until well blended. Roll out about 1/3 inch thick on floured board. Cut in small squares. Bake on a greased cookie sheet at 325-F about 15 minutes. When cold, cover with boiled icing and sprinkle with colored sugar. Source: Pennsylvania Dutch Cook Book - Fine Old Recipes, Culinary Arts Press, 1936.