Make cake circles. Prepare batter following recipe directions Tint half red. Bake and cool 1/2 in. high cakes according to pan package directions. Use smallest round (1 3/4 in.) cutter from set to cut two cake circles per treat from red tinted cake. Use small star Cut-Out to cut three cake stars per treat from white cake.
Assemble treat pops. Prepare buttercream icing following recipe directions. Tint a portion blue; reserve some white. Push red cake circle into bottom of treat pop. Use tip 2A and white icing to pipe a swirl of icing from back edge following the curves of the container, then filling the center. Repeat to add one more layer of cake and icing.
Use tip 2A and blue icing to pipe a thin layer of icing over white icing. Position three cake stars around inside of container. Use tip 2A and blue icing to fill in icing around cake stars and to the top.