For chocolate mousse cake, one should layer the cake with chocolate mousse. The cake will cut neatly if it is well chilled.
Decorations: To make chocolate shavings, use a potato peeler and pull it evenly across the bar of chocolate at room temperature.
To make chocolate scribbles, melt some plain chocolate and allow to cool slightly. Fill a small piping bag with the melted chocolate and pie scribbles on baking paper.
Allow to set to hard in the fridge and carefully lift the scribbles off the paper to decorate the cake.
To make chocolate leaves, melt plain chocolate and brush the melted chocolate over the underside of clean, dry rose leaves.
Leave to set in the fridge, then carefully peel away the leaves and you should be left with chocolate copies.