Combine the milk and cream in a heavy-bottomed saucepan over a medium-low heat. Scrape in the vanilla seeds, add the pod and slowly heat almost to boiling point - but don't boil or scorch the milk. Meanwhile, beat the egg yolks and sugar in a large bowl with a mixer on high speed until pale and creamy and sugar has dissolved.

Remove the vanilla pod from the hot milk mixture. Slowly whisk the milk mixture into the egg and sugar, a little at a time. Return mixture to the saucepan and cook over a very low heat to create a custard. Stir until custard thickens and coats the back of a spoon (about 5 minutes, but don't scramble the eggs - if using a thermometer, cook to 82°C).

Place gelatine in a bowl of cold water and soak until soft. Remove the gelatine, squeeze it gently and stir into the warm custard. Strain the custard through a fine sieve into a bowl and leave to cool.

Melt the shaved chocolate in a double boiler over gently simmering water. Stir the chocolate into the custard, cover, and chill in the fridge. When the custard starts to set around the edges, whip the cream until thick. Fold into the bavarois.

Lightly oil four 125ml dariole moulds and spoon in the mixture, tapping the moulds to avoid air pockets. Chill in the fridge until firmly set - about 4 hours.

To serve, gently tip the bavaroises onto a plate and sprinkle with grated chocolate.