Line 9-inch square pan with Reynolds Wrap Aluminum Foil, with ends of foil extending over sides.
Mix cookie crumbs and butter; press onto bottom of pan.
Beat cream cheese, sugar and vanilla in large bowl with mixer until light and fluffy.
Add 2 cups COOL WHIP; beat on low speed until blended.
Spread over crust. Freeze 4 hours or until firm.
Microwave remaining COOL WHIP and chocolate in microwaveable bowl on HIGH 1 min.; stir until chocolate is completely melted and mixture is well blended. Cool slightly. Use foil handles to lift cheesecake from pan.
