Stir pudding powder, sugar, rum and 5 tablespoons of milk until smooth. Boil up the rest of the milk. Bind with the pudding powder. Let the pudding cool down, stirring several times
Stir the sour cream, double cream and vanilla sugar until smooth. Layer the sour cream and chocolate pudding alternately in 4-6 glasses (each containing approx. 150 ml). Chill for at least 1 hour
Chop the couverture separately and melt in a hot water bath. Alternately spread on a smooth surface (e.g. marble plate or back of a baking tray). As soon as they begin to set, use a spatula to plane them off into shavings. Decorate the cream with it