Clean, wash, halve and stone the plums. Stir 2 tablespoons grape juice and starch until smooth. Boil up the rest of the juice, lemon juice, cinnamon and sugar. Add plums and simmer for 3-5 minutes (depending on maturity). Thicken with the starch and continue cooking for about 1 minute. Leave to cool
Mix yoghurt, vanillin sugar, pistachios and possibly liqueur. Whip cream until stiff and fold in
Layer plums and yoghurt cream in a large dessert bowl. Decorate with chocolate-mint bars and mint leaves
For dessert you can also take plums from the jar. You don't need extra grape juice to cook compote with the juice, and the yoghurt cream tastes great with rum or rum flavouring instead of mint.