LINE 9-inch square pan with foil, with ends of foil extending over sides. Finely crush 24 cookies. Mix with butter; press onto bottom of prepared pan.
BEAT cream cheese and peanut butter in medium bowl with whisk until blended. Add milk and dry pudding mix; beat 2 min. Stir in 1 cup COOL WHIP; spoon over crust. Refrigerate until ready to use.
MICROWAVE remaining COOL WHIP and chocolate in microwaveable bowl on HIGH 1-1/2 to 2 min. or until chocolate is completely melted and mixture is well blended, stirring after each minute. Cool completely.
SPREAD chocolate mixture over pudding layer in pan. Chop remaining cookie; sprinkle over chocolate mixture. Refrigerate 4 hours or until firm. Use foil handles to lift dessert from pan before cutting to serve.