Preheat oven to 350°. Beat butter, cream cheese and granulated sugar until blended. Beat in egg and vanilla. In another bowl, whisk flour, milk powder and baking powder; gradually beat into creamed mixture. Chill dough 30 minutes or until slightly firm., Scoop level tablespoonfuls of dough; roll in confectioners’ sugar. Place 1 in. apart on parchment-lined baking sheets. Bake until light brown, 10-12 minutes. Remove from pans to wire racks to cool.