PREHEAT oven to 350° F.
TOSS cookie crumbs and butter together in medium bowl. Press onto bottom of ungreased 9-inch springform pan.
BAKE for 10 minutes.
MICROWAVE broken white baking bars in medium, uncovered, microwave-safe bowl on MEDIUM-HIGH (70%) power for 1 minute; STIR. If pieces retain some of their shape, microwave at additional 10 to 15-second intervals, stirring just until melted. Cool to room temperature.
BEAT cream cheese, sugar and vanilla extract in large mixer bowl until smooth. Beat in eggs. Gradually beat in melted white baking bars. Spread over chocolate crust.
BAKE for 40 to 50 minutes or until edges are set but center still moves slightly. Cool in pan on wire rack; refrigerate until firm.
DUST cocoa over over cheesecake before serving.
TIP:To dust the cheesecake, place cocoa in a small, fine mesh strainer and tap over the cheesecake.