Put milk in a saucepan, add the vanilla pod and heat gently until it just reaches boiling point.
Whisk together egg yolks and sugar until pale and fluffy.
Ladle 1/3 of the milk onto the egg yolk mix, scrape down the sides of the bowl, and blend in well.
Remove vanilla pod
Add custard mix to remaining milk and stir over a gentle heat to thicken.
Stir in grated chocolate until completely dissolved.
Add water to gelatine them warm until the gelatine has completely dissolved, then cool for 2 mins.
Combine 1-2 tbsp of the custard into the gelatine, then slowly pour the blend into the rest of the custard, stirring continuously.
Pour custard into a bowl and place over a bath of ice cubes, stir continously until thick but still flowing.
Lightly whip 3/4 of the double cream.
Whisk the egg whites into soft peaks.
Add a little of the chocolate custard to the whipped cream, then add that to the rest of the custard and combine well.
The mix should now be on the point of setting, pour it onto the whisked egg whites and fold in quickly.
Pour into serving bowls and refrigerate to set.
6 servings