PREHEAT oven to 350°F. Grease 9-inch-square baking pan.
PLACE semi-sweet morsels and butter in large, microwave-safe bowl. Microwave on HIGH (100%) power for 1 minute; STIR. The morsels may retain some of their original shape. If necessary, microwave at additional 10- to 15-second intervals, stirring just until mixture is melted. Add brown sugar and peanut butter to chocolate mixture; beat on medium speed for 1 minute or until well mixed. Beat in eggs and vanilla extract. Gradually stir in flour. Stir in white and peanut butter & milk chocolate morsels. Spread into prepared pan. Drop jam by spoonfuls onto batter. Swirl with a knife.
BAKE for 35 to 40 minutes or until wooden pick inserted in center comes out still
slightly sticky. Cool completely in pan on wire rack. Cut into bars.