Oh la la.
Authentic French onion soup is hard to beat. Rich in both color, texture, and flavor, French onion soup epitomizes everything that a soup can be.
Lots of onions get cooked down until they are practically liquefied. Then, the pot gets deglazed and stock is added to make a rich, deep brown broth before topping with toasted baguette, Comté or Gruyère cheese, and broiled until bubbly.
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French onion soup, called soupe à l’oignon gratinée in French, originated centuries ago. According to competing legends, the soup was invented in 18th century France, either at the court of Louis VX or at the Palme d’Or restaurant.
Today, the soup is considered a good hangover cure in France.
The magic of French onion soup lies in the true caramelization of the onions. That’s caramelization, mind you. Not browning. There is a difference.
Browning is a protein reaction. Here, it would mean letting the onions sear on the pot bottom, gaining color that way through a Maillard reaction.
Caramelization, on the other hand, involves sugar — not protein. Here, that means a low and slow cooking down process, whereby the onions brown not because the pot singed that color on, but because the slow cooking process breaks down the natural sugars.
Recipe Notes: Authentic French Onion Soup
Let’s talk about the all-important wine pairing. (We are channeling France, after all.) French onion soup is warm and rich, so it wants a zippy, berry-forward counterpoint to cut through the heaviness.
For a red wine, a high acidity/low alcohol red pairs perfectly, especially a nice Beaujolais, or other Gamay, according to Wine Spectator. An Italian Dolcetto or French pinot noir could also work.
White wine is especially good with French onion soup. Choose a pinot gris, Viognier, or Gewürztraminer.
Some other French onion soup recipe notes:
- The onions are not really done until they have reduced down to the world’s most delicious sludge. See the photos above.
- Everyone’s onions will be a little different, so I hesitate to give exact salt quantities, or specify an amount of sugar. Sugar can deepen the flavor of the onions if yours are not already naturally sweet enough from the caramelization, but can be easily overdone.
Make It Family Style!
You don’t have to buy special French onion soup crocks (or alternatively, ramekins) to make this. You can serve this French onion soup family style. Here’s how:
- When the soup is completed except for the baguette and cheese, transfer it to an oven-safe sauté pan with sufficiently high sides, or even a casserole.
- Layer baguette slices and the cheese over the entire top. Broil and serve.
Did you make this Authentic French Onion Soup recipe? How was it?
Authentic French Onion Soup
- 3 pounds yellow onions (about 6 medium)
- 3 tablespoons butter
- large pinch sugar (optional)
- 2 teaspoons kosher salt, or to taste
- 1 cup dry white wine
- 1 quart (4 cups) unsalted chicken stock
- 3 cups cold water
- 2 bay leaves
- 5 sprigs fresh thyme
- 2 cups (8 ounces) freshly-grated Gruyère of Comté cheese
- 1/2 baguette, sliced 1/2" thick, maybe a little less
For the Soup
- Peel, cut in half through the root end, and thinly slice the onions.
- Heat the butter in a wide-bottomed pot over medium-low heat. Add the onions, thyme, bay leaves, and 1 teaspoon of salt. Cover the pot and reduce the heat to low. Cook, stirring often, until the onions have turned extremely soft and a deep golden brown, about 45 to 50 minutes. Tip: Stir often. You want the onions to caramelize, not brown or burn. Adjust the heat as necessary.
- Remove the lid shortly before the onions have finished cooking, to evaporate the liquid. The bottom and low sides of the pot should form a deep brown crust.
- Raise the heat to medium. Deglaze the pot with the white wine, scraping the brown bits and stirring. Let the liquid fully evaporate so that the pot forms another brown crust. Deglaze the pot with 1 cup of water, stirring and scraping as above until the liquid evaporates. Repeat with 1 more cup of water.PRO TIP: Why not just dump three cups of liquid all at once and let it evaporate? Because this way, you are building three times the rich brown caramelization that forms on the pot.
- At this point, the onions should look chestnut brown and soft to the point of being the world's most delicious sludge pile. Add the quart of chicken stock and 1 cup of water. Bring to a boil, then lower the heat and let simmer, partially covered, for about 30 minutes. Stir occasionally.
- While the soup simmers, place four French onion soup crocks on a rimmed baking sheet. Grate the cheese and toast two baguette slices per crock. Set aside.
- Taste the soup for seasoning. It should be fairly thick. Adjust with a large pinch of sugar if necessary, and an additional teaspoon of salt or so.
- Preheat the broiler and position the rack about 7" from the top of the oven. Spoon the soup into the crocks, leaving a little space from the rim. Lay a slice or two of baguette over the soup, and generously top with cheese.
- Place the soup under the broiler until melted and bubbly and lightly browned on top, about 3 or 4 minutes. (Keep an eye on it!) Let rest for 2 minutes before serving. The top of the crocks are extremely hot, so take care.