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 tsp 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 it in the refrigerator for at least an hour.
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 350F for 10-12 minutes or until the edge is JUST turning golden brown.
