Method

  1. Prepare the onions and toppings

    French Onion Soup: Prepare the onions and toppings

    Halve and peel 1000 g of yellow onions, then slice them from root to stem into thin, even half-moons. Peel 2 garlic cloves and mince it. Cut 170 g of baguette into one sturdy slice per serving, each about 2 cm (3/4 in) thick, and grate 140 g of Gruyere cheese. Keep the bread and cheese separate while the soup cooks.

  2. Soften the onions

    Melt 42 g of unsalted butter in a wide, heavy pot over medium heat. Add 1000 g of yellow onions and 3 g of fine sea salt, toss thoroughly, and cover. Cook for 10 minutes, stirring once halfway through, until the onions have softened and released a noticeable amount of liquid.

    10:00

  3. Caramelize the onions

    Uncover the pot and reduce the heat to medium-low. Cook for 45 to 60 minutes, stirring every 5 minutes at first and more often as the onions darken. When a brown film forms on the pot, add a small splash of water and scrape it into the onions. Begin checking at 45 minutes; continue until the onions are very soft, reduced in volume, and an even deep amber without blackened edges.

    00:45:00
    00:05:00

  4. Build and simmer the soup

    Stir 2 garlic cloves into the onions and cook for 30 seconds until fragrant. Sprinkle in 16 g of all-purpose flour and stir for 1 minute so no dry flour remains. Pour in 15 ml of sherry vinegar and scrape the bottom of the pot, then gradually add 1200 ml of unsalted beef stock while stirring. Add 4 fresh thyme sprigs, 2 bay leaves, and 1 g of black pepper. Bring the soup to a gentle simmer, partially cover, and cook for 20 minutes. Remove and discard the thyme sprigs and bay leaves, then taste and adjust the seasoning only if needed.

    00:00:30
    00:01:00
    00:20:00

  5. Toast the baguette

    While the soup simmers, heat the oven to 200°C (400°F). Arrange 170 g of baguette on a baking sheet and bake for 8 to 10 minutes, turning once, until dry at the center and lightly golden at the edges. Begin checking at 8 minutes so the slices stay sturdy rather than brittle.

    08:00

  6. Gratinate and serve

    French Onion Soup: Gratinate and serve

    Switch the oven to high broil and place an oven rack so the tops of the bowls will sit about 15 cm (6 in) from the heat. Set broiler-safe soup bowls on a rimmed baking sheet, ladle in the hot soup, and place one toast on each bowl. Divide 140 g of Gruyere cheese evenly over the bread. Broil for 2 to 4 minutes, watching continuously, until the cheese is fully melted, bubbling, and browned in spots. Begin checking at 2 minutes. Let the bowls stand for 2 minutes, warn diners that the rims are very hot, and serve immediately.

    02:00
Cook's noteThe onions determine the soup's depth. Stop only when they are uniformly deep amber and soft enough to press into a paste with the back of a spoon; pale onions make a thin-tasting broth, while scorched onions make it bitter.

Smart Substitutions

  • No Gruyere? Use Comte, Emmental, or a well-aged Swiss-style cheese that melts smoothly and browns under the broiler.
  • No beef stock? Use a full-flavored unsalted mushroom stock; the soup will be lighter but still savory.
  • No sherry vinegar? Use red wine vinegar or apple cider vinegar in the same amount.
  • No baguette? Use sturdy sourdough or country bread cut thick enough to float without dissolving.

Tips and Variations

  • Use a wide pot rather than a narrow saucepan so moisture can evaporate and the onions brown evenly.
  • Grate the cheese finely enough to melt before the bread edges become too dark under the broiler.
  • Set every bowl on a rimmed baking sheet before filling it; the sheet catches drips and makes the hot bowls easier to move together.

What Went Wrong?

  • Onions are still pale after 45 minutes Keep cooking over medium-low heat and stir more often. A crowded or narrow pot can add 10 to 20 minutes.
  • Onions are catching or turning black Lower the heat immediately and scrape in a small splash of water. Remove any truly burned pieces before continuing.
  • Soup tastes too sweet Add a few drops of sherry vinegar and a small pinch of salt, then taste again before adding more.
  • Cheese browns before it fully melts Move the oven rack slightly farther from the broiler and use a finer, more even layer of cheese.

Nutrition Estimate

Calories490
Protein25 g
Carbs52 g
Fat21 g
  • Fiber: 5 g per serving
  • Sodium: 975 mg per serving

Nutrition disclaimer:This recipe is provided for general cooking information only. Nutrition values are estimates and may vary by ingredients, brands, preparation methods, and serving sizes. Check ingredient labels and follow appropriate food-safety practices. This content is not medical, dietary, allergy, or professional food-safety advice.

soupFrenchcomfort foodbistro

FAQ

Can French onion soup be made without wine?Yes. This version is designed without alcohol; slow caramelization supplies depth, while unsalted beef stock and sherry vinegar provide savory body and balance.
Why does onion caramelization take so long?A large quantity of onions must first release and evaporate its water before steady browning can begin. Gentle heat develops sweetness without scorching the edges.
Do the bowls have to be broiler-safe?Yes, when gratinating the soup in individual bowls. As an alternative, broil the cheese-topped toasts on a baking sheet and place one on each bowl just before serving.