Put the mussels in a pan over high heat with plenty of pepper, but no water.
Cook them for about 5 minutes, until they open. Discard any that remain closed.
Drain and save the broth.
Transfer them to a deep dish.
Strain the broth through a sieve lined with muslin and pour into a bowl.
Add parsley and stir.
Pour the broth over the mussels and serve.