Combine butter, sugar, cream cheese, egg and vanilla in large bowl. Beat until light and fluffy. Add flour, beat until well mixed. Wrap in saran wrap and refrigerate 2 hours or until firm.
Preheat oven to 375°. Roll dough out to 1/8 inch thickness on lightly floured surface. Cut dough with lightly floured 2 inch heart shaped cookie cutter. Place cutouts 1 inch apart on ungreased cookie sheets.
Bake 7 to 10 minutes or until edges are very lightly browned. Remove immediately to wire racks to cool completely.
Melt chocolate chips and shortening in small saucepan over low heat, or double boiler until melted. Dip half of each heart into melted chocolate. Refrigerate on cookie sheets or trays lined with waxed paper until chocolate is firm. Store, covered in refrigerator with wax paper in between.