Heat the milk in a pot. Roughly chop the chocolate and melt it over a warm water bath. Let the milk slowly soak into the chocolate, stirring constantly. Let cool down
Whip the cream with the whisks of the hand mixer until stiff. Carefully fold the cream into the chocolate. Cover the mousse and chill for approx. 3 hours
Meanwhile wash the plums, cut them in half and remove the stone. Put 200 ml water, port wine, vanillin sugar, sugar and cinnamon in a pot. Stir starch and 3-4 tablespoons of water until smooth. Bring the port wine mixture to the boil, stir in the cornflour, bring to the boil again while stirring
Add plums, bring to the boil and simmer for 2-3 minutes. Stir several times. Pour into a bowl and let cool off. Wash lemon balm, dab dry and pluck leaves from the stalks
Use a large ice-cream scoop to form balls from the mousse. Arrange some compote on dessert plates with mousse, decorate with lemon balm and possibly chocolate rolls. Add the rest of the compote
waiting time approx. 3 1/2 hours