Cookie crumbs should come from 18 Cream Filled Cookies that have been finely crushed. ** This 6 ozs of Chocolate chips should be melted and cooled slightly . Combine crumbs and margarine; press onto bottom of 9-inch springform pan. Combine 24 ozs of cream cheese and sugar, mixing at medium speed on electric mixer until well blended. Add eggs, one at a time, beating well after each addition. Blend in sour cream and vanilla; pour over crust. Combine remaining 8 ozs cream cheese and melted chocolate, mixing at medium speed on eletric mixer until well blended. Add Red Raspberry preserves; mix well. Drop rounded measuring tablespoonsfuls of chocolate cream cheese batter over plain cream cheese batter, do not swirl. Bake at 325 degrees F., 1 hour and 25 minutes. Loosen cake from rim of pan; cool before removing rim of pan. Melt chocolate pieces and whipping cream over low heat stirring until smooth.