1. Heat the milk until almost boiling.
2. Beat the yolks, egg, and sugar together until thick and white, and add the hot milk, stirring well.
3. Return the mixture to the pan and cook, without boiling, until the custard thickens, stirring all the time. Strain
4. Break up the chocolate roughly and melt it in the water, either in a double saucepan or in a basin over hot water.
5. Add the melted chocolate to the hot custard, and leave to cool.
6. Whip the cream until semi-stiff and fold it into the custard mixture with the vanilla essence.
7. Turn into a suitable container.
8. Chill until thoroughly cold, cover closely and half freeze
9. Beat the mixture well. Re-freeze until firm; label and store.
10. Ice creams made with an electric ice cream maker are prepared somewhat differently, and the manufacturer's directions should be followed