Dip the cranberries in the egg white, then roll in caster sugar a few times until well coated. Leave to set (or use glac cherries instead, even easier and no need to frost with egg white).
Brush just the top of the cake with a little jam.
Roll out the marzipan to slightly larger than the top of the cake, lay on top of the cake, press down and trim flush to the edges of the cake.
Mix a dribble of water at a time into the fondant icing sugar, until its a smooth, stiff consistency that wont run. Pile on the top of the cake. Push to the edges with a palette knife so it eases down the sides a little. Make a wreath from the sage and bay, then add a few of the frosted cranberries (or glac cherries if using instead).
