Assemble treat pops. Prepare buttercream icing following recipe directions. Tint portions dark rose, rose and light rose. Push mini whoopee pie into bottom of treat pop. Use tip 12 and dark rose icing to pipe a swirl of icing from back edge following the curves of the container, then filling the center. Repeat to add three more layers of cake with rose and light rose icing. Use tip 32 and light rose icing to pipe swirl on top of treat pop.