I got ideas for this cake from several on this site, so thank you all for the great inspiration! This was for my daughter's third "rainbow" birthday. Three batches of scratch white cake to make 6 layers. Frosting is buttercream and rainbow is made with melted candy wafers. This was a big cake! I originally wanted 12" pans but accidentally bought 10". By the time I realized I was too busy to exchange them. It would have made the layers thinner, thus making the cake wider and much easier to slice! Regardless, it was super yummy and everyone is still raving about it! I also made the yellow "sun cake" as I was disillusioned that there wouldn't be enough!