Moules Marinière

• 4 quarts (4 liters) mussels, weighing about 6 lb. (2.8 kg)
• 4 new onions

Mussels should be tightly closed or—if they are open—should close tightly when scraped or tapped with the blade of a knife; if they stay open, it means they are dead and could be dangerous if eaten (don’t worry, however, if the mussels open and close after being cleaned: they are simply breathing).

Clean the mussels one by one, scraping off any barnacles or mud, and pulling out the litt