Soupe à l'Oignon Gratinée — Print Recipe

Deeply caramelized onions melted into a rich beef broth, ladled into a crock and crowned with a crusty crouton and a bubbling, golden blanket of molten Gruyère cheese. This Parisian classic is winter warmth distilled into a single, magnificent bowl.

Ingredients

1.5kg yellow onions (about 6 large), thinly sliced
60g butter
2 tablespoons olive oil
1 teaspoon sugar
2 tablespoons all-purpose flour
250ml dry white wine
1.5L rich beef stock
2 tablespoons cognac or brandy
4 thick slices sourdough or baguette, toasted
250g Gruyère cheese, grated
2 sprigs fresh thyme
2 bay leaves
Salt and freshly ground black pepper

Instructions

1 Melt butter with olive oil in a large, heavy-bottomed pot over medium heat. Add all the sliced onions and stir to coat. Cook for 10 minutes, stirring occasionally, until the onions soften and release their liquid.
2 Reduce heat to medium-low, add the sugar, and continue cooking for 35-45 minutes, stirring every few minutes, until the onions are deeply caramelized to a rich mahogany color. Do not rush this step; patience creates depth of flavor.
3 Sprinkle the flour over the caramelized onions and stir for 2 minutes. Add the white wine and cognac, scraping up any caramelized bits from the bottom of the pot.
4 Pour in the beef stock, add thyme and bay leaves, and bring to a simmer. Cook uncovered for 20 minutes to meld the flavors. Season generously with salt and pepper.
5 Preheat your broiler to high. Ladle the hot soup into oven-safe crocks or bowls placed on a baking sheet.
6 Float a toasted bread slice on top of each bowl and pile generously with grated Gruyère, letting the cheese hang over the edges of the crock.
7 Broil for 3-5 minutes until the cheese is bubbling, golden, and irresistibly melted with charred spots. Let cool for 2 minutes (the crocks will be extremely hot) and serve immediately.

Did You Know?

French onion soup was historically considered peasant food because onions were plentiful and cheap. Legend credits King Louis XV with reinventing it late one night at a hunting lodge, using only onions, butter, and champagne.