Prepare the mussels as described in the first step on
Add the potatoes to the cooking juices in the pan, re-cover and cook gently for 15 minutes or until the potatoes are cooked through, adding a little water if the pan runs dry. Meanwhile, remove about two-thirds of the mussels from their shells, discarding any closed shells.
Place the parsley and cream in a food processor and process until the parsley is finely chopped. Pour into the pan. Bring to the boil and boil briefly until the juices have thickened slightly. Return all the mussels to the pan and heat through gently for a couple of minutes. Season with pepper and a little salt and serve in bowls.