Cream the butter and cream cheese together till nice and creamy. Add the sugar slowly unless you like sugar all over your counter (which I have done once or twice). The confection sugar is light and flies easily so be careful and beat till fluffy. Blend in the egg and add the vanilla extract beat till completely mixed. Complete the dough by slowly adding the flour and baking powder.
Chill the dough for 1 to 2 hours, I also stick the pans in the refrigerator at the same time. Depending on how long your oven takes to come up to the 350° temperature will determine when to start your oven.
Line your pan with parchment paper or a silicone mat. Take out of the refrigerator the cookie dough and shape into 1 inch balls. Roll the balls around the superfine sugar and place about 1 ½ inches apart. I just take 2 fingers and lightly press on the top of each ball just to flatten a little.
Bake for 9-12 minutes and they will look white with just a hint of golden brown along the edges. They may look underdone but when you leave them on the cookie pan for about a minute this helps to firm them up a little. At this point move them to a cooling rack to finish.
When completely cooled I take a sifter and add a little of the confectioner sugar then I just light dust each cookie. Makes about 2 dozen. Store in air-tight container for 3-5 days.