Press Chocolate Wafer Crust mixture on bottom and 1 cm up the sides of a 25 cm springform pan. Pre-bake as crust recipe directs. Place chocolate morsels in top of a double boiler; bring water to a boil. Reduce heat to low; cook until chocolate melts. Beat cream cheese at high speed of an electric mixer until light and fluffy; gradually add sugar, mixing well. Add eggs, one at a time, beating well after each addition. Stir in melted chocolate, cocoa, and vanilla; beat until blended. Stir in sour cream, blending well. Pour into prepared pan. Bake at 150ºC or 1 hour and 40 minutes (center may be soft but will firm when chilled). Let cool to room temperature on a wire rack; chill at least 8 hours. Garnish each serving with whipped ----