Let dough stand at room temperature for 5-10 minutes to soften. Press into an ungreased 13-inch by 9-inch baking dish; sprinkle with peanut butter chips. Bake at 375° for 15-18 minutes or until lightly browned and edges are firm to the touch. Cool on a wire rack. In a small bowl, beat frosting and peanut butter until smooth. Spread over bars. Drop jam by teaspoonfuls over frosting; cut through frosting with a knife to swirl the jam. Yield: 2 dozen.