French Onion Soup
- 10m Prep Time
- 1h Cook Time
- 1h Ready In
A classic French onion soup with deeply caramelized onions in a rich beef broth, topped with a cheesy crouton. Slow-cooking the onions brings out their natural sweetness, while Gruyère cheese adds a savory finish.
Ingredients
- 29.6 ml olive oil
- 907 g yellow onions thinly sliced
- Kosher salt
- 3.7 ml all-purpose flour
- 29.6 ml cognac or dry white wine
- 1 low-sodium beef broth
- 1 bay leaf
- 3 sprig fresh thyme
- 7.39 ml sherry vinegar
- 4 thin slices country bread
- 42.5 g Gruyère cheese finely grated
Nutrition (per serving, estimated)
Estimated based off 7 of 11 identified ingredients (per 100 g food data, scaled by amount).
Vitamins & minerals
- Calcium: 46.2 mg
- Iron: 1.3 mg
- Magnesium: 8.65 mg
- Phosphorus: 31.1 mg
- Potassium: 54.2 mg
- Zinc: 0.24 mg
Let's Prepare
Collect
Gather these ingredients — no prep needed yet.
- 29.6 ml olive oil
- Kosher salt
- 3.7 ml all-purpose flour
- 29.6 ml cognac or dry white wine
- 1 low-sodium beef broth
- 1 bay leaf
- 3 sprig fresh thyme
- 7.39 ml sherry vinegar
- 4 thin slices country bread
Prepare
- 907 g yellow onions, thinly sliced
- 42.5 g Gruyère cheese, finely grated
Let's Cook
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Step 1.
Heat 2 tablespoons olive oil in a medium heavy stockpot over medium heat. Add the thinly sliced yellow onions and ¾ teaspoon kosher salt, then reduce the heat to low. Cook, stirring occasionally, until the onions are tender and have released their liquid, about 10 minutes.
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Step 2.
Increase the heat to medium-high and continue cooking, stirring often and scraping the bottom of the pot, until the onions are deep brown and caramelized, 40 to 50 minutes. If the bottom of the pot starts to get too dark, add 2 to 3 tablespoons water to deglaze.
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Step 3.
Sprinkle the caramelized onions with ¾ teaspoon all-purpose flour and cook, stirring, for about 2 minutes. Stir in 2 tablespoons cognac or dry white wine and cook for about 1 minute.
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Step 4.
Add 1 (32-ounce) container low-sodium beef broth, 1 bay leaf, and 3 large sprigs fresh thyme. Bring to a simmer and cook until the liquid reduces to about 4 cups, 18 to 20 minutes. Discard the bay leaf and thyme sprigs, then stir in ½ tablespoon sherry vinegar.
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Step 5.
While the soup simmers, heat the broiler. Arrange 4 thin slices country bread on a rimmed baking sheet and sprinkle with 1½ ounces finely grated Gruyère cheese and some additional fresh thyme leaves. Broil in the top third of the oven until golden brown and bubbling, about 1 minute.
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Step 6.
Ladle the soup into bowls and top each with a cheesy bread slice. Serve immediately.