For the sour cherry and curd cream, first pit the sour cherries and bring to the boil once briefly in a saucepan with sugar. Remove from the heat and let it get really cold in the refrigerator.
Then stir the curd with (liquid) whipped cream and vanilla sugar until smooth. If desired, also stir in a small dash of cherry liqueur or brandy. Add sour cherries including juice, stir gently and pour into decorative bowls or dishes.
Chill for at least 2 hours, preferably longer, covered with cling film (otherwise takes on refrigerator scents). Sprinkle the sour cherry and curd cream with coarsely grated chocolate and/or pistachios before serving.