Cream the butter and sugar together. Slowly add flour, working it in well. Add the well beaten eggs and mix thoroughly. Chill over night.
Roll out thin on a floured board. Cut out cookies. Brush cookies with the egg whites which have been slightly beaten. Sprinkle with sugar and cinnamon. Press ½ pecan or walnut in to the center of each cookie.
Bake in 350 degree oven about 10 minutes or until golden brown. Allow to cool before eating.