In a large bowl, combine sugar, butter, cream cheese, salt, almond and vanilla extracts, and egg yolk. Beat until smooth. Stir in flour until well blended. Chill the dough for 8 hours, or overnight. Preheat oven to 375 degrees F (190 degrees C).
On a lightly floured surface, roll out the dough 1/3 at a time to 1/8 inch thickness, refrigerating remaining dough until ready to use. Cut into desired shapes with cookie cutters. Place 1 inch apart on ungreased cookie sheets. Leave cookies plain for frosting, or brush with slightly beaten egg white and sprinkle with candy sprinkles or colored sugar. Bake for 7 to 10 minutes in the preheated oven, or until light and golden brown. Cool cookies completely before frosting.
keep an eye on them while baking, they have to stay white, if you let them golden too much they will be a little rocky.