I made this for my sister's little granddaughter. The cake is actually WASC, however it is not white. This is my first rainbow cake and lurking under the white chocolate ganache and white chocolate MFF, are six brilliant colors. And there is no sour cream. Instead, the flavor is cheesecake. So, I guess it is not a WASC after all!
I would like to acknowledge the person whose cake I copied here, but I had saved the pic on my hard drive so am not sure of the source. So thanks, whoever you are.