For the Crème Chantilly:
Place the cream and milk in a cold bowl and whisk over a bowl of ice and water until it forms soft peaks. Stir in the vanilla sugar.
For the crème pâtissière
Heat the milk with the vanilla pod
and leave to infuse for 30 minutes. Mix the egg, egg yolk, sugar and flour
in a bowl. Remove the vanilla pod from the milk and stir the milk into the egg mixture. Return to the saucepan, which has been rinsed out, and cook over a low heat stirring all the time. At this stage, the mixture often appears lumpy but it becomes smooth when boiled. Simmer for 3-4 minutes while stirring. Pour into a bowl and cover with cling film or damp greaseproof paper to prevent a skin forming. One to two teaspoons of vanilla sugar maybe added instead of infusing the milk with a vanilla pod.
For the chocolate glacé icing :
Place the chocolate in a bowl with the water and butter and melt over a pan of hot water. Remove from the heat and beat until smooth. Stir in the sifted icing sugar adding extra hot water if necessary to give a coating consistency.