Preparation

• Preheat oven to 325°F if using silver 9-inch springform pan (or to 300°F if using a dark nonstick 9-inch springform pan). Mix wafer crumbs and margarine until well blended. Press firmly onto bottom of pan; set aside.
• Beat cream cheese in large bowl with electric mixer on medium speed until well blended. Add 1/2 cup of the sour cream, the granulated sugar, cocoa powder, flour and vanilla; beat until well blended. Add eggs, one at a time, beating on low speed after each addition just until blended. Pour over crust.
• Bake 50 to 55 min. or until center is almost set. Run knife or spatula around rim of pan to loosen cake; cool before removing rim of pan. Refrigerate at least 4 hours or overnight.
• Mix remaining 3/4 cup sour cream and the powdered sugar. Serve spooned over cheesecake. Store leftover cheesecake in refrigerator.