Cream butter and cream cheese in a large mixer bowl. Beat in sugar until
smooth. Beat in egg and vanilla. Stir in flour and baking powder. Chill
several hours.
Preheat oven to 375 degrees. Roll dough into small balls. Place on ungreased
cookie sheet. Flatten with a glass that has been dipped in vanilla sugar
(sugar in which you have stored a vanilla bean) or plain sugar.
Bake 10 to 15 minutes, until the edges are lightly browned. Cool on wire
racks. Makes 36 cookies