White Velvet Sugar Cookies

2 cups butter, softened

1 (8 oz) pkg cream cheese, softened

2 cups sugar

2 egg yolks

1 tsp. vanilla

4 ½ cups flour

-Cream butter and cream cheese until light and fluffy. Add sugar, egg yolks and vanilla; mix well.  Gradually add flour. Cover and chill 2 hours or until firm.  Roll out on floured surface to ¼ inch thickness.  Cut into 3-inch shapes; place on greased baking sheets.  Bake at 350 degrees for 10-12 minutes or until set (but not browned).  Cool 5 minutes.  Place on wire racks to cool.