If you bake the sponge ... for a plain icing, just use milk. Beat with an electric whisk until smooth, pale and fluffy, then spread smoothly over the top of the cake with a spatula. To decorate ...

use a piping bag fitted with a plain 3mm/⅛in nozzle). Pipe yellow dots into the middle of each daisy. Set aside to dry, at room temperature, for 1-2 days. For the cake, line the base of a deep ...