Soupe a l'Oignon Gratinee

Melt the butter

Melt the butter in a large heavy pot over medium heat until it foams.

Caramelize the onions

Add the onions and sugar, stir to coat, and cook low and slow, stirring occasionally, until the onions turn deep mahogany brown and jammy.

Deglaze with wine

Pour in the white wine and scrape up the browned bits stuck to the bottom of the pot.

Simmer the soup

Add the stock, bay leaf and thyme, bring to a simmer, and cook uncovered until the flavors meld into a deep savory broth.

Toast the bread

While the soup simmers, toast the baguette slices under the broiler until lightly golden on both sides.

Assemble and broil

Ladle the soup into oven-safe bowls, float a toasted bread slice on top, cover generously with grated Gruyere, and broil until the cheese bubbles and turns golden brown.

Serve

Let the bowls cool for a minute before serving, as the cheese top will be scalding hot.