Few dishes feel as cozy and satisfying as a well-made French onion soup. It’s simple at heart—onions, broth, bread, and cheese—but the magic comes from patience and care. This version is rich, deeply savory, and topped with a golden, bubbling cap of Gruyère.
You don’t need fancy equipment or chef tricks, just time and attention. If you love comforting meals that taste like home, this one’s for your regular rotation.
What Makes This Special
This recipe leans into slow, steady caramelization, which builds a deep, slightly sweet onion flavor that anchors the soup. A splash of dry wine and a hint of vinegar add brightness and balance the richness.
The broth is layered—mostly beef for body, with a bit of chicken or vegetable stock to round out the flavor. Thick slices of toasted baguette soak up the broth without falling apart, while the cheese melts and browns to a gorgeous crust. It’s classic, but approachable and unfussy.
Shopping List
- Yellow onions (6–8 medium, about 3 pounds), thinly sliced
- Unsalted butter (4 tablespoons)
- Olive oil (1–2 tablespoons)
- Kosher salt and freshly ground black pepper
- Granulated sugar (optional, 1/2 teaspoon to aid browning)
- Garlic (2–3 cloves), minced
- Dry white wine or dry sherry (1/2 cup)
- Beef broth (6 cups), low-sodium
- Chicken or vegetable broth (2 cups), low-sodium
- Bay leaves (2)
- Fresh thyme (4–6 sprigs) or 1/2 teaspoon dried thyme
- Worcestershire sauce (1–2 teaspoons)
- Apple cider vinegar or red wine vinegar (1–2 teaspoons)
- Baguette (1 loaf), sliced into 1/2–3/4-inch rounds
- Gruyère cheese (8–10 ounces), grated
- Optional: splash of brandy or cognac (1 tablespoon), Swiss or Comté cheese for blending
Instructions
- Prep the onions. Peel and slice the onions pole-to-pole into thin half-moons.
Aim for even slices so they cook uniformly.
- Start the base. Heat a large, heavy pot or Dutch oven over medium heat. Add butter and olive oil. When the butter foams, add the onions and 1 teaspoon salt.
Toss to coat.
- Caramelize slowly. Cook the onions over medium to medium-low heat, stirring every few minutes. If they look dry, add a splash of water to loosen brown bits. This step takes 40–50 minutes.
You want deep golden brown, jammy onions—no rushing.
- Boost browning (optional). If the onions won’t take color, sprinkle in 1/2 teaspoon sugar after 20 minutes. Keep stirring to avoid scorching.
- Add aromatics. Stir in the garlic and cook 1 minute, until fragrant. Increase heat to medium-high.
Pour in the wine (or sherry) and scrape up the browned bits. Let it reduce by about half, 2–3 minutes.
- Add the broths and herbs. Pour in the beef broth and chicken or vegetable broth. Add bay leaves and thyme.
Bring to a simmer, then reduce heat and gently simmer for 25–30 minutes. Skim any foam.
- Season and balance. Remove bay leaves and thyme stems. Stir in Worcestershire, vinegar, and brandy if using.
Taste and adjust salt and pepper. The flavor should be deep, savory, and slightly bright.
- Toast the bread. While the soup simmers, arrange baguette slices on a baking sheet. Toast in a 375°F (190°C) oven until crisp and lightly golden, about 8–10 minutes, flipping once.
This helps them hold up in the soup.
- Assemble for broiling. Ladle hot soup into oven-safe bowls placed on a sturdy baking sheet. Float 1–3 toasted slices on top of each bowl, then cover generously with grated Gruyère (and a little Swiss or Comté if you like).
- Broil to finish. Set the oven rack 6 inches from the broiler. Broil until the cheese is melted, bubbling, and browned in spots, 2–5 minutes.
Watch closely to avoid burning.
- Serve carefully. Let the bowls cool for a minute. The melted cheese will be hot and stretchy. Serve with a simple salad or roasted vegetables.
Storage Instructions
Cool the soup to room temperature, then store it in airtight containers in the fridge for up to 4 days.
Keep the bread and cheese separate until serving. Reheat the soup gently on the stovetop until steaming, then assemble with fresh toasts and cheese before broiling.
For longer storage, freeze the soup (without bread or cheese) for up to 3 months. Thaw overnight in the fridge, reheat, and finish with the toast-and-broil step.
Avoid freezing the cheese-topped bowls; they can split and lose texture.
Health Benefits
- Onion power: Onions are rich in antioxidants like quercetin and sulfur compounds that may support heart health and reduce inflammation.
- Protein and minerals: Using a good-quality broth provides protein, collagen, and minerals such as iron and zinc—especially if you opt for bone broth.
- Portion-friendly: This soup is satisfying thanks to the fiber in onions and the richness of the cheese, which helps with fullness. You can adjust the bread and cheese to fit your goals.
- Balanced comfort: Pair with a crisp salad or steamed greens for a more nutrient-dense meal without losing the cozy factor.
Common Mistakes to Avoid
- Rushing the onions: Insufficient caramelization leads to flat flavor. Plan for at least 40 minutes and adjust heat to prevent scorching.
- Overcrowding a small pot: Too many onions in a small pan steam instead of brown.
Use a wide, heavy pot for even caramelization.
- Skipping deglazing: Those browned bits on the bottom are flavor gold. Wine or sherry lifts them into the soup; don’t miss this step.
- Using only one type of stock: A blend of beef with a little chicken or vegetable stock creates a more nuanced base than beef alone.
- Soggy bread: Untoasted bread falls apart. Toast it well so it stays sturdy under the cheese.
- Underseasoning: Taste at the end.
A small splash of vinegar and the right amount of salt brighten the entire pot.
Recipe Variations
- Vegetarian version: Use vegetable stock and add a splash of soy sauce or miso for depth. Choose vegetarian Worcestershire or a bit of balsamic for umami and sweetness.
- Mushroom boost: Sauté sliced cremini or shiitake mushrooms with the onions for a meatier flavor and extra texture.
- Cheese blend: Mix Gruyère with fontina or Comté for extra melt and flavor. A touch of Parmesan on top helps browning.
- No-wine option: Swap wine for extra broth plus 1 teaspoon apple cider vinegar.
You’ll still get balance without alcohol.
- Gluten-free: Use gluten-free baguette or toasted bread and confirm your broth is gluten-free.
- Make-ahead dinner: Caramelize onions the day before and refrigerate. The next day, add broth and finish the soup in under 30 minutes.
FAQ
What’s the best onion for French onion soup?
Yellow onions are the classic choice because they balance sweetness and savoriness. You can mix in a couple of red onions for color or sweet onions for a milder profile, but yellow keeps it grounded and rich.
Can I make this without broiling?
Yes.
Ladle hot soup into bowls, top with toasted bread and cheese, then bake at 400°F (200°C) until melted and golden, about 10–12 minutes. It won’t blister as quickly as under a broiler, but it still turns out great.
How do I avoid burning the onions?
Use medium to medium-low heat, a heavy pot, and stir every few minutes. If the pot looks dry or brown bits are getting too dark, add a tablespoon of water to loosen and lower the heat slightly.
Is wine necessary?
No, but it adds complexity.
If you skip it, add a bit more vinegar at the end or a splash of sherry vinegar to mimic that bright note. The soup will still be rich and satisfying.
What cheese works if I can’t find Gruyère?
Swiss, Emmental, or Comté are good substitutes. Aim for a cheese that melts well and has a nutty flavor.
Avoid very sharp cheddar, which can turn greasy.
Can I use store-bought broth?
Absolutely. Choose low-sodium broth so you control the salt. If it tastes flat, add a splash of Worcestershire, a dash of soy sauce, or a small knob of butter for roundness.
Why add vinegar at the end?
A small splash wakes up the flavors and cuts through the richness of the cheese and onions.
It makes the broth taste more lively without turning it sour.
How can I make it lighter?
Use more vegetable broth, reduce the cheese slightly, and serve with a bigger salad. You still get the cozy flavors without the heaviness.
Final Thoughts
French onion soup rewards patience with deep, layered flavor and a beautiful cheesy crust. Once you’ve caramelized onions a few times, the process feels relaxing, not fussy.
Keep good bread on hand, grate your cheese fresh, and finish with a quick broil for that classic look. Whether it’s a chilly weeknight or you’re hosting friends, this bowl brings a warm, timeless comfort to the table.