Heat milk (up to 4-5 tablespoons) with pieces of broken chocolate and split open vanilla pod while stirring. Separate eggs and beat egg whites until stiff. Stir egg yolks with sugar until foamy, stir in cornstarch and remaining milk.
While stirring chocolate milk, bring to a boil again.
Add yolk cornstarch milk mixture, beat briefly while on stove and fold egg whites into warm mixture and remove vanilla pod.
Rinse form with cold water and pour in pudding and leave to cool.
Before serving, remove from mold and serve to taste with vanilla sauce and whipped cream.