Wash and clean the leek, carrots and celery. Cut the leek and carrots into fine rings, finely chop the onions and celery. Place the mussels in a basin or bowl and wash under cold running water. Do not use broken and open mussel shells for consumption.
Fill a large saucepan a quarter with water, add the vegetables, mussel spices and all the other spices. Cook for about 20-30 minutes. Add the mussels and the white wine and cook gently for about 10-20 minutes with the pot closed. During cooking, carefully use a ladle to carefully lift the mussels back into the stock.
Arrange the opened mussel shells on a soup plate and pour the stock over them. Black bread with butter is served with it.