Cream butter & cream cheese together in a large bowl.
Add sugar, vanilla, & egg yolk to cream cheese mixture.
Flour will have to be added slowly, & mixed by hand.

Roll out dough on a floured surface; cut with seasonal cookie cutters.
Bake at 350 degrees for 6-8 minutes.

Cool on cookie sheet for 2 minutes, then cool on a rack.

Frost with a cream cheese frosting (this can be purchased ready-made at most grocery stores in the baking section.)