Clean and wash the Brussels sprouts. Bring the stock to the boil. Add the sprouts and cook for about 25 minutes at low heat. In the meantime, peel the skin off the sausage, halve the sausage and cut into thin slices. Wash chives and parsley, dab dry and cut into rings or chop.
Puree the Brussels sprouts in the stock with the cutting stick of the hand mixer, bring to the boil and stir in potato powder. Add slices of sausage. Season soup with salt, cayenne pepper and nutmeg. Serve sprinkled with the herbs