Mix the custard powder in part of the cold milk. Heat the rest of the milk with sugar and crumbled chocolate, stirring often, bring to the boil. Add the mixed pudding powder, bring to the boil. Pour the pudding into a bowl, let it cool, stirring occasionally.
Whip the cream with the cream stiffener and vanilla sugar until stiff, leave something to garnish, pull the rest into the pudding. Pour into a nice glass bowl or into portion bowls, decorate with whipped cream and possibly wedges of mandarin. Put in a cool place for approx. 1 hour before application.
The consistency of this chocolate pudding is more like a cream - so it cannot be overturned!