Wash, halve, stone and dice the plums. Sort blackberries, wash if necessary. Caramelise 3 tablespoons of sugar in a pot. Add plums and 3 tbsp. water. Cover and cook over a low heat for 8-10 minutes. Stir starch with 1 tablespoon of cold water until smooth. Bind the compote with it. Add blackberries. Let the compote cool down.
Crumble Russian bread. Mix yoghurt and 3 tablespoons of sugar. Whip the cream until stiff, adding vanilla sugar. Approx. 1⁄4 Fill cream into a piping bag with star-shaped spout. Fold the remaining cream into the yoghurt.
Ca. 2⁄3 Pour yoghurt into a bowl. Put Russian bread and half a compote on top. Mix the rest of the compote, except for 1 tablespoon, with the rest of the yoghurt and place it on the compote in the bowl. Pour cream in a piping bag on the cream, decorate with the rest of the compote. Keep cool until serving.