This homemade tiki hut beach cake was actually made for a bridal shower instead of a birthday. I made this cake using a 1/2 sheet cake for the base and a 3-layer 6-inch cake for the tiki hut. The sheet cake is yellow cake and the layer cake is chocolate cake.
I cut the two bottom layers down as follows: The bottom layer is cut evenly to four layers. The next level is cut at an angle, so that the top of the layer is a little smaller than the bottom of the layer. I "shaved" the sides of the top (3rd) layer, so that the middle was a little higher than the sides. This made the hut have the appearance of having a more pointed roof-line.
Everything on the cake is edible, except the trees and the umbrella. I started with a crumb coat on the sheet cake, and then I place the 3-layer cake on top, and crumb-coated it as well. Next, I frosted the water with a blue buttercream icing. I mixed blue and green icing gel to get the color I wanted for the "tropical" water. I used an icing spatula to create "waves" in the water.
I used crushed vanilla wafers for the sand. The beach towels are made from Fruit Roll-Ups that I cut, so they would look like they had stripes. I added a bit of brown icing gel to make the icing for the grass roof on the hut and around the cake. To make the walls of the hut, I added a TINY bit of black icing gel to the brown. I used a basket-weave icing tip to make the walls of the hut, and a grass tip to make the roof and the border of the cake.
Be sure to secure the 3-layer cake to the sheet cake with a wooden dowel rod that runs down to the cake board.