On a floured board sift 2 cups flour. You will require 2½ cups unsalted butter, the yolks of 6 eggs and 1 cup icing sugar with which a vanilla pod has been pounded and sifted. With the tips of the fingers very lightly work in one-sixth of each of the ingredients until all of each of them has been worked in. It may take more flour, depending upon the size of the yolks of the eggs and the quality of the butter. Only add enough flour to roll. Roll to about ¼ inch thickness. Cut with a round cookie cutter of any size that suits, but not more than 2½ inches in diameter. Place on cookie sheets and bake in 300° oven for about ¼ hour. The cookies should not be coloured. When done remove very carefully from cookie sheet with a metal spatula. They are as fragile as they are exquisite. Cover generously with sifted icing sugar. Do not put in tin box until cold. If the box has a cover that closes hermetically, the cookies will keep for two weeks or more.
A staple for over sixty years in the Stein/Toklas household.
SOURCE: The Alice B Toklas Cook Book