PREPARE cake batter and bake in 2 (9-inch) round layer pans as directed on pkg. Cool 10 min. in pans; remove cake layers to wire racks. Cool completely.
SPREAD 1 of the cake layers with jam; cover with remaining cake layer. Cut cake crosswise in half. Stack regular Oreo Cookies in line down centre of large cake board or tray to form the "butterfly's body," securing cookies to each other with small amount of the whipped topping. Arrange cake stacks around body to resemble the butterfly's wings.
SPREAD remaining whipped topping onto cake stacks. Decorate wings with ring-shaped hard candies and Mini Oreo Cookies. Store in refrigerator.