Not totally sure who decided it should go into cake form but I've seen it around quite a bit. I know that Whisk Kid was featured on Martha Stewart making it.
I put a cake up for our workplace charitable campaign silent auction, and someone contacted me asking if I could re-create this cake to bring in for her group. I was happy to give it a go. I had made a rainbow cake once before, but it was more like a zebra cake with rainbow colours.
|cutting the cake|
I used the super easy vanilla cake recipe I had and dyed it using gel colours from Wilton. I had to modify the recipe slightly because it had to be lactose-free, but it was easy with some lactose-free milk subsitituted in.
I did use Whisk Kid's Italian Meringue Buttercream tutorial. I found it to be very comprehensive and although I am way too lazy to start making this frosting every time I make a cake, I will definitely keep the tutorial handy when I want something that is light and smooth, with not too much sweetness. I used about 9 egg whites and found it was enough to do the whole cake by only putting a thin coat between each layer.
What a fun cake and for a good cause! I hope they all enjoyed.