Stir yeast in water; let stand 5 to 10 minutes. Cream butter thoroughly; gradually blend in flour. Add yeast to butter and flour. Form dough by teaspoonful into a ball. Press each ball flat in granulated sugar (sprinkled on foil); first one side, then the other. Bake on ungreased cookie sheet in 375 degree oven 15 to 20 minutes. NOTE: for variety, cinnamon or finely chopped pecans (or any kind of nuts) may be added to the granulated sugar. (At Christmas, sprinkle a little red and green sugar on cookies)