1/2 medium onion, chopped
1 tablespoon olive oil
1 cup dry white wine
3 lb mussels (preferably cultivated), scrubbed and beards removed
Garnish: fresh flat-leaf parsley sprigs and lemon wedges

Cook onion in oil in a 5- to 6-quart pot over moderate heat, stirring, until
softened, 3 to 5 minutes.
Add wine and mussels and bring to a boil. Cover and cook, shaking pot
occasionally, until mussels are opened, 4 to 5 minutes.
(Discard any unopened ones.)

Transfer mussels to a platter with a slotted spoon, discarding steaming liquid.

Serves 12 (as part of a�oli menu).