Place one cake on a work surface right side up. Using a knife, slice off the top of the cake to create a smooth surface. Cut the outline of a smaller circle inside the cake leaving about 2-3 inches from the edges. Scoop out the middle of the cake with a spoon, careful not to puncture the bottom or sides of the cake.
Repeat with the second cake.
Place one cake on a cake stand or serving plate. Using it as glue, frost the top edge of one cake. Fill the cake with candy and place the other cake on top with the wide edges meeting together.
Using a rubber spatula, frost a layer of the vanilla icing on the whole cake. Take your fruit roll-up snack and tear it into 1-inch pieces. Starting at the bottom of the cake, place each fruit roll-up 1-inch piece next to the other. Continue to layer the fruit pieces around the cake until you have reached the top of the cake. The fruit pieces will give a paper fringe look of a piñata.