Clean the cauliflower and divide into florets. Peel and slice carrots and kohlrabi. Clean, wash and cut the savoy cabbage into pieces. Add everything to the vegetable stock and simmer for about 20 minutes.
For the cheese balls, stir the fat until foamy. Grate cheese finely. Stir cheese, flour and egg yolk into the fat. Season with salt, pepper and nutmeg. Wash and finely chop the parsley and stir in. Chill the mixture briefly and then form small balls.
Pour into boiling salt water and leave to stand for 5 minutes. Drain. Season soup with salt, pepper and Worcester sauce and add the cheese balls just before serving.