- For the cake:
- 1 1/2 sheets store-bought vanilla cake
- 3 cups cream cheese frosting, divided
- 3 cups ground graham crackers
- For the shells:
- 4 cups brown sugar
- 2 cups colored candy melts, melted
- Make the cake: In a large bowl, crumble cake with your hands and mix with one cup of frosting. Cake will be moist and will resemble wet sand. Press into a new sandcastle mold and place in the freezer for up to 1 hour.
- Make the shells: While the cake is setting in the freezer, make the seashell decorations. Pack the brown sugar in a 9 by 13 casserole dish. Press assorted shells into the sugar, creating a clean indent. Pour candy melts into shell indents and place in the fridge for up to 30 minutes. Remove hardened shells and brush off any remaining sugar.
- Assemble the cake: Remove cake from the freezer and place upright on a cooling rack with a baking sheet underneath. Lift mold off the cake to reveal a sandcastle. Melt remaining cream cheese frosting and pour over the cake. Cover cake with graham cracker crumbs to resemble sand. Decorate with chocolate seashells. Cake will keep up to 4 days covered in the fridge.