Preheat oven to 350-375* depending on your oven. Mix dry ingredients until blended, adding softened butter and egg until a thick dough forms. Drop by teaspoonfuls onto cookie sheet, 1-2 inches apart. Bake 7-9 minutes....LET COOKIES COOL COMPLETELY!
Filling: Mix softened butter, powdered sugar, and vanilla till fluffy.. chill in fridge for about ten minutes.. when cookies are completely cool.. pile up the filling and make sandwiches...YUM!