1 Put the milk into a pan and bring to the boil. Beat the egg yolks with the vanilla seeds until foamy, gradually trickling in the sugar.
2 Pour the hot milk on to the egg yolk mixture, stirring constantly with a whisk. Return the mixture to the pan and reheat, stirring, until it thickens slightly. Then remove from the heat. Do not let it boil!
3 Melt the chocolate and 3 tbsp cream in a bain-marie, stirring, then mix into the egg and milk mixture with the cocoa. Cool in the refrigerator for about 1 hour.
4 Lightly whip the rest of the cream and fold into the chocolate milk mixture. Transfer to an ice cream maker and freeze for about 30 minutes. Alternatively transfer to a metal dish and put into the freezer for about 4 hours, stirring vigorously every hour.
5 Scoop out with an ice cream scoop, pile a few scoops in each dish and serve immediately.