Mussels in Cidre-Cream Sauce

1.5 kg mussels, preferably moules de bouchot
3 shallots
125 g butter
1 tablespoon flour
250 ml French cider
salt
pepper
2 tablespoons crème fraîche
1 bunch of parsley

Clean the mussels with a brush under running water; remove their beards. Throw away any open mussels that don't close when you tap them with your finger. They could be dead already and inedible. Cut any green off the shallots, and peel off their outer skin. Cut them into quarters, then into small pieces, then put them into a large, heavy pot, preferably an enamelled cast-iron one, and brown them in the butter. Sprinkle the flour over them; allow it to cook over a gentle heat in the butter for a half a minute. Add the cleaned mussels, cover the pot and cook at high heat for 5-7 minutes, until all the mussels have opened. During that time, pick up the pot and shake it two or three times. In the meantime, chop the parsley finely. When the mussels are done, add the cider to the sauce, then season carefully with salt and pepper. Mix the crème fraîche and parsley with the mussels, discarding any that haven't opened.

And here's a tip: dishes with shellfish and fish gain greatly from being seasoned with sea salt.