Beat together margarine and cream cheese until well blended. Add flour, 3/4 cup powdered sugar and cream; mix on low until well blended. Wrap dough in waxed paper and refrigerate 2 to 4 hours. Roll out dough onto floured waxed paper to 1/4-inch thickness. Cut into shapes and place 1 inch apart on ungreased cookie sheets. Make an indentation in center of each cookie and fill with preserves. Bake at 375° for 15 minutes, or until very, very lightly browned. Transfer to wire racks and cool completely. Store between waxed paper sheets in tightly sealed container. Just before serving, sprinkle with powdered sugar. Yield: 80 (2-inch) cookies.