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 prepared pan.
Melt 4 oz. chocolate as directed on package. Beat cream cheese spread in large bowl with mixer until creamy. Gradually beat in milk, then melted chocolate. Whisk in COOL WHIP; pour over crust.
Freeze 6 hours. Meanwhile, make chocolate curls from remaining chocolate.
Remove dessert from freezer 15 min. before serving; let stand at room temperature to soften slightly. Use foil handles to lift dessert from pan; cut into squares. Garnish with chocolate curls.