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 electric 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. Spread over cheescake. Chill.
Garnish with additional whipping cream, whipped, raspberries and fresh mint leaves, if desired.