In the past, this hearty onion soup with melted cheese on top was served from the late-night hours into the early morning in the Les Halles market district of Paris. Now, it is served at all times of the day in France. Commonly referred to as one of the great soupes de santé, restorative "soups for the sick," this flavorful broth is said to work equally well on curing the flu as it does on relieving hangovers.
