In a stand mixer fitted with a paddle attachment, cream the butter, salt, and sugar together until light and fluffy.
Add the egg yolks while mixing.Scrape down sides of the bowl.
Add 2 teaspoons vanilla extract.
Pour in the flour mixture and mix until incorporated.
Roll the dough into a log.Wrap in parchment paper or plastic, then chill in the refrigerator for at least an hour.The best way to keep the dough from flattening out on the bottom is to pop it into an empty cardboard paper towel roll.
Once the dough is chilled sprinkle sanding sugar on a clean surface.Unwrap the dough and roll in the sugar.
Use a sharp knife to cut dough into slices of even thickness.
Place cookies on a parchment lined baking sheet and bake at 350 for 10 to 12 minutes or until the edge is just turning brown.
