Description
This Best French Onion Soup is a cozy, bistro‑style classic with deeply caramelized onions, a rich, savory broth, and a golden, bubbly Gruyère crust. It’s slow-simmered for layers of flavor, finished with a splash of wine and brandy, and served with toasted baguette for the ultimate comfort in a bowl.
Ingredients
Scale
- 1 tablespoon olive oil
- 2 tablespoons unsalted butter
- 5–6 large yellow onions, thinly sliced
- 1 teaspoon sugar
- 1 teaspoon salt, plus more to taste
- 2 cloves garlic, minced
- 2 tablespoons all-purpose flour
- ½ cup dry white wine (optional but recommended)
- 6 cups beef stock or beef broth, preferably low-sodium
- 1 teaspoon fresh thyme, or ½ teaspoon dried
- 1 bay leaf
- ½ teaspoon black pepper
- 1 tablespoon brandy or sherry (optional, traditional touch)
- For Serving
- Baguette slices, toasted
- 1½–2 cups Gruyère cheese, freshly grated
Instructions
- Caramelize the onions: Heat the olive oil and butter in a large heavy pot over medium heat. Add the sliced onions, sugar, and salt. Cook, stirring frequently, for 30–40 minutes until the onions are very soft, deeply golden, and caramelized. Adjust the heat as needed so they brown slowly without burning.
- Add garlic and flour: Stir in the minced garlic and cook for 1 minute until fragrant. Sprinkle the flour over the onions and cook, stirring constantly, for 2–3 minutes to remove the raw flour taste.
- Deglaze with wine: Pour in the dry white wine, scraping up any browned bits from the bottom of the pot. Simmer for 2–3 minutes until slightly reduced.
- Simmer the soup: Add the beef stock, thyme, bay leaf, and black pepper. Bring to a gentle simmer and cook uncovered for about 30 minutes to let the flavors meld.
- Finish and season: Remove and discard the bay leaf. Stir in the brandy or sherry if using. Taste and adjust with more salt and pepper as needed.
- Prepare the topping: Preheat the oven to 400°F (205°C). Ladle the hot soup into oven-safe bowls set on a baking sheet. Top each bowl with toasted baguette slices and a generous handful of grated Gruyère.
- Broil: Transfer the baking sheet to the oven and broil for 2–4 minutes, watching closely, until the cheese is melted, bubbly, and lightly browned. Serve hot.
Notes
- Take your time with the onions—true caramelization can take 40 minutes or more.
- Low-sodium broth lets you control the salt level at the end.
- If you skip the wine and brandy, add a squeeze of lemon or a splash of vinegar to brighten the flavors.
- Use oven-safe bowls or crocks that can handle broiling.
- Soup can be made ahead; add bread and cheese just before serving and broil.
- Prep Time: 20 minutes (plus 30–40 minutes to caramelize onions, overlapping with cook time)
- Cook Time: 50–60 minutes
- Category: Soup
- Method: Stovetop & Broil
- Cuisine: French
Nutrition
- Serving Size: 1 bowl (about 1½ cups soup with bread and cheese)
- Calories: Approx. 420
- Sugar: Approx. 10 g
- Sodium: Approx. 980 mg (will vary with broth)
- Fat: Approx. 22 g
- Saturated Fat: Approx. 12 g
- Unsaturated Fat: Approx. 9 g
- Trans Fat: 0 g (varies with butter used)
- Carbohydrates: Approx. 35 g
- Fiber: Approx. 3 g
- Protein: Approx. 18 g
- Cholesterol: Approx. 55 mg
Keywords: best French onion soup, classic French onion soup, caramelized onion soup, Gruyère onion soup, bistro onion soup