If you have a nautical or beach themed wedding.
The photographer writes:
Rosa and Dave were married in Hawaii and came home to celebrate. This cake was inspired by their beach-theme. Cool blue fondant is decorated with handpainted chocolate seashells, shimmer-dusted pearls, and sugared royal icing coral. The cupcakes were done in a "lei" flower-like design.
keywords: shell wedding cakes, shells decorating wedding cakes, blue cake