Just looking at this splendid rainbow concoction from Whisk Kid with its 12 alternating layers of cake and icing makes me feel a bit queasy. Even with my own birthday cake I usually eat the cake and leave most of the icing behind on the plate (it's not a diet thing - I don't have that kind of willpower - I just find a lot of icing kind of gross). But if it were in front of me, I just know I would have to go for one bite to say I did. I bet as you chew it icing starts to push its way out of your mouth until you resemble a sweet-smelling rabid dog.
You can find the recipe at Whisk Kid but we warned it's as much work as it looks - you have to bake six cakes to make up all of the layers. And use an oil drum's worth of icing.
Thanks to Iullia for sending this to me. No, really. Despite my less than appetizing descriptions this is a really cool cake!
Just a note...one of my brothers is a pilot and while he was flying recently he saw a rainbow, full circle. He wasn't able to get a shot of it but if he did it would look something like this which was taken from a tower in Canberra: