Blend the butter, cream cheese, sugars and egg yolk. Sift flour and baking powder and add to the creamed mixture. Mix well and chill for at least 1/2 hour.

Roll out like pie dough and cut into 3 inch squares. Add about a tablespoon of filling in the center of each square. Loosely fold 2 opposite corners over and to the center, leaving the other 2 open.

Place on a slightly greased cookie sheet and bake in a preheated oven for 10 to 15 minutes until golden brown. Cool slightly and dust with confectioner's sugar. Cool completely. Store in an air-tight container.