Preheat oven to 350ºF. Mix cookie crumbs and margarine; press onto bottom of 9-inch square baking pan. Melt 2 oz. chocolate as directed on package.
Beat cream cheese, sugar and vanilla with mixer until blended. Add melted chocolate; mix well. Add eggs, 1 at a time, mixing on low speed after each just until blended. Pour over crust.
Bake 25 to 28 min. or until center is almost set. Cool 5 min.; spread with jam. Melt remaining chocolate square; drizzle over cheesecake. Cool cheesecake completely. Refrigerate at least 4 hours. Cut into 24 bars.
