Birthday cake for 20 small kids - how big? What kind of icing?

[florenceuk]

DS(will be 5) wants either Jupiter (for which a big round cake with a red spot might do) or an early humans cake (cavemen with woolly mammoth). Any ideas and guidance as to how big a cake and what kind of icing might work best much appreciated! DH thought I needed edible decorations - what could I make them out of? Would plastic cavemen be OK?

Hiya - I usually make birthday cakes in a 10 by 10 inch square tin and use icing plus plastic figures to decorate. Many children tend not to really eat the cake anyway, just suck the icing off - unlike my own children who eat the cake and leave the icing! Anyway my rather rambling point is a)yes, plastic decorations are fine as you'll be removing them before cutting the cake and b) this sort of cake will cut into 20 very small pieces which should be fine.

bump - anybody got a preferred cake recipe and/or icing recipe?