Clean, wash and chop the rhubarb. Boil 3/8 l water and juice. Add rhubarb and simmer for about 4 minutes. Stir starch and 3 tbsp. water until smooth and thicken rhubarb. Season to taste with about 3 tbsp. sugar. Cool down
Bring the milk and lemon peel to the boil. Sprinkle semolina, 1 tablespoon sugar and vanillin sugar. Remove the pot from the stove. Cover and let it swell for about 5 minutes. Stir in egg
Cut off the semolina with 2 teaspoons of dumplings. Cook in boiling salted water for about 10 minutes. Arrange the rhubarb groats on 4 deep plates and arrange the semolina dumplings on top. Decorate with lemon balm as desired
The season for rhubarb runs from April to the end of June. So that you can enjoy it afterwards: simply cut it into pieces, scald and freeze