Drain the plums and collect the juice. Mix 2 tablespoons of juice and starch. Boil up the rest of the juice and the cinnamon stick. Stir in starch and bring to the boil again. Carefully fold in plums and let the compote cool down.
Put milk in a bowl, add dessert powder and mix for about 1/2 minute. Stir in quark, lemon peel and vanillin sugar. Pour semolina into dessert bowls and let it set for about 10 minutes. Spread compote on top. Sprinkle with almonds and decorate with lemon balm