A must on your Christmas cookie tray. Despite the lemony frosting, the cinnamon flavor comes through. On a pastry board, mix flour, sugar and walnuts. Form a mound, make a well and add the egg yolks, lemon rind and spices. Cut the butter in small pieces and add to the flour mixture. Knead thoroughly to make a smooth dough. Let dough rest for 30 minutes in the refrigerator. Preheat oven to 350�. Roll dough out with a rolling pin to 1/8inch thick and cut into star shapes with a cookie cutter. Bake at 350� until cookies are lightly browned, about 10 minutes. Let cool and decorate with the icing. To make icing, mix sugar, egg white, lemon juice and yellow food coloring (if using) in a bowl until very smooth. (Icing has to be thick enough so it will not run off stars.) Spread evenly with a pointed knife on the stars. Let icing dry overnight. Store in a cookie tin. Note: If you like a less sweet cookie, omit the icing. Yield: 6 dozen. Franziska Mayer, Washington, DC Randy Shearer