This link shows you how to apply icing on a cake. You need to put a thin cake of icing cream. And then freeze the cake to make the icing cream hard before applying the rest of the icing cream.
A genoise is an Italian sponge cake named after the city of Genoa and closely associated with Italian and French cuisine. It is a whole-egg cake, unlike some other sponge cakes for which yolks and eggwhites are beaten separately. The eggs, and sometimes extra yolks, are beaten with sugar and heated at the same time using bain-marie or flame, to a stage known to patissiers as "ribbon stage". A genoise is generally a fairly lean cake, getting most of its fat from egg yolks, but some recipes also add in melted butter before baking.