1. Combine flour, baking powder and salt in a bowl; set aside. In mixer bowl, beat butter and sugar until fluffy, 3 minutes. Beat in yolks and vanilla. Add flour mixture and combine. Wrap dough in plastic wrap, chill 1 hour.
2. Roll dough to 3/8 inch thick on a floured surface. Cut as desired. (Dough scraps can be re-rolled up to 2 times.) Bake at 350 degrees for 10 to 12 minutes. Cookies can be stored airtight for up to 5 days. Makes 36 two-inch cookies.