Decorate in Order:
1. Ice cake smooth in white buttercream icing.
2. Using black buttercream icing, pipe tip 3 outlines for stained glass on cake and cookie.
3. Using yellow, pink, violet, blue and green piping gels in cut parchment bags, fill in stained glass areas.
4. Using white buttercream icing, pipe tip 3 bead border on top edge of cake.
5. Using white buttercream icing, pipe tip 21 shell bottom border.
6. Position cookie on cake top.