Beat the egg, egg yolks, sugar and vanilla sugar over a warm water bath with the whisks of a hand mixer for approx. 7 minutes until creamy. Then beat the cream over a cold water bath until cold. Fold in mascarpone and chestnut puree. Soak the gelatine. Warm up the grappa. Squeeze the gelatine, dissolve in the warm grappa and mix with a little cream. Then stir into the rest of the cream. Put it in a cold place. Whip cream until stiff. As soon as the cream starts to gel, fold in the cream. Put the mousse in a cool place for about 1 hour.
Wash the grapes, dab dry and cut in half. Put grape juice, lemon juice and icing sugar in a pot and bring to the boil. Let cool down. Add the grapes to the stock and chill for 1-2 hours. Cut out dumplings from the mousse. Serve with the marinated grapes. Decorate with mint
waiting time 2-3 1/4 hours