Coarsely chop the chocolate coating and melt in a bowl over a warm water bath. Remove from the stove and allow to cool slightly. Whip cream until stiff and chill
Separate eggs. Whisk 2 egg yolks, 1 tablespoon sugar and vanilla sugar in a bowl (or kettle) over a hot water bath until creamy. Stir the couverture and 2 tbsp. whipped cream into the egg mixture. Beat the egg whites until stiff. Using a whisk, carefully stir the remaining cream into the egg-sugar mixture. Finally, fold in portions of beaten egg white and fill the mousse into a small mould or bowl. Chill for about 4 hours
Chop the pistachios finely. Pour 2 egg yolks, 1 tbsp. sugar, starch and wine into a mixing bowl (or beating pot) and beat in a hot water bath until thick and frothy. Fold in the pistachios to 1 tsp. Cut out dumplings from the mousse with a hot spoon and arrange on plates. Add the sabayone and sprinkle with the remaining pistachios.
waiting time approx. 4 hours