This impressive rainbow cake ... put the 20cm/8in cake board on top. Put a dab of buttercream on the cake board and place the purple sponge on top. Spread a ¾cm/½in thick layer of buttercream ...

Flavored mousse is spread between the layers. Written by Eloise Kirn and produced by David Fang Follow INSIDER Food on Facebook Follow INSIDER on YouTube More from Lifestyle Billy Angel Cake ...