Wash the berries and pluck the elderberries from the panicles. Cook the berries in about 1 liter of boiling water with the lemon zest and the cinnamon stick for about 10 minutes.
Then pour into a sieve and collect the juice. Peel the apples, remove the core and cut into wedges. Bring the berry juice with the apple wedges, half of the salt and 125 g sugar to the boil.
Mix the cornstarch with water and thicken the soup with it. For the semolina dumplings: bring the milk, butter and the rest of the salt and sugar to the boil.
Add the semolina and cook to a thick paste while stirring. Finally fold in the eggs. Shape dumplings - add them to the soup, leave to steep for another 10 minutes.