CUT cake into 8 slices; cut each cake slice in half. Line bottom and side of 9-inch pie plate with cake slices; set aside.
PLACE cottage cheese, milk and chocolate in blender container; cover. Blend on high speed until smooth. Add pudding mix and whipped topping; cover. Blend on low speed 1 minute, stirring once. Pour into prepared pie plate.
REFRIGERATE 3 hours or until set. Store leftover pie in refrigerator.