For crust: Combine vanilla wafer crumbs, hazelnuts, sugar and melted butter in medium bowl and blend thoroughly. Pat mixture into bottom and sides of 8-inch springform pan. Refrigerate until firm, approx 30 minutes. Preheat oven to 300 degrees. Bake crust 15 minutes. Let cool completely. For Filling: Preheat oven to 350 degrees. Beat cream cheese at low speed in large bowl of electric mixer until smooth. Gradually beat in 1 cup sugar. Add eggs and creme de cocoa and blend until completely smooth, stopping once to scrape down sides of bowl. Pour into cooled crust. Bake until set, about 45-50 minutes. Let cool slightly. (Retain oven temperature at 350 degrees.) Combine sour cream and remaining sugar in medium bowl and blend well. Using rubber spatula, spread mixture over cheesecake to within 1/2 inch of edge. Bake 5 minutes. Preheat broiler. Run cheesecake under broiler, watching carefully, until top is lightly browned, about 1-2 minutes. Let cool. Refrigerate at least 5 hours, or overnight. Cheesecake can be refrigerated up to one week. Set the hazelnut in center of cake before serving. Serves 8-12. This taken from my mother's recipe collection, she got this one watching KTHV-11, Little Rock, on "Arkansas Today" Show, _Cooking with Don Bingham_, Sep 26, 1990.