Wash the mussels well and cook them with wine, bay leaves and peppercorns in a large saucepan for about 5 minutes. Shake or stir frequently.
Then remove the mussel meat from the shell (discard closed mussels) and place in an ovenproof dish. Let the mussel stock boil down to halfway. If you want to do it faster, put some of the brew in a bowl.
Fry the chopped onions and squeezed garlic in a pan. Season to taste with the cream and the boiled or bottled mussel stock, finely chopped parsley, lemon juice and salt. Then pour over the mussels. Heat everything at 250 degrees for 5-10 minutes.