Cream butter and cream cheese in a medium mixing bowl; beat until fluffy. Add flour, then mix well.
Roll dough to 1/8-inch thickness on a lightly floured surface; cut with a 2-inch round cutter. Place 2 inches apart on lightly greased cookie sheet. Spoon 1/4 teaspoon of the jam on each cookie; fold opposite sides together slightly overlapping edges.
Bake at 375°F for 15 minutes.
Remove to wire racks to cool; sprinkle with confectioners' sugar.
Makes about 2 dozen cookies.