In a large saucepan, melt 30 gr of
butter and then add the finely chopped
onion, the
thyme and leave to sweat, covered, for 5 min. Add the white
wine. Bring to a boil and
season with a little
salt and a generous amount of freshly ground
pepper. Add the
mussels, cover and cook for 8 min. Be careful to only use open
mussels (throw away those that are closed). Set them aside. Filter the
cooking juices and also set aside.