Put the hard cooked egg yolks through a wire sieve. (To do this easily, press them through with your fingers). Add the raw egg yolks and mix well.
In a large bowl, cream the butter and sugar; add the egg mixture and mix thoroughly. Stir in the flour, cardamon, and lemon zest; blend well. Chill dough for 1 hour.
Roll out small portions of the dough at a time on a lightly floured board to 1/8" thickness. Cut with a 2 1/2" cookie cutter. Brush with egg white, then sprinkle the tops with the sugar and almond mixture.
Place on ungreased cookie sheet.
Bake for about 10 minutes, or until delicately browned.