French Onion Soup Recipe With Chicken Broth, From Scratch

French onion soup is a French bistro-style soup of slowly browned onions, savory broth, toasted bread, and melted cheese. This version uses chicken broth for a lighter, mellow base, while patient caramelizing and a splash of wine build the deep flavor that makes each bowl satisfying.

Ingredients

3 lb yellow onions (1.36 kg), peeled and thinly sliced
3 tbsp unsalted butter (42 g)
1 tbsp olive oil (15 ml)
1 tsp fine salt (6 g), plus more to taste
1/4 tsp black pepper (0.5 g)
1/2 cup dry white wine (120 ml), or extra chicken broth
6 cups low-sodium chicken broth (1.42 L)
2 sprigs fresh thyme (about 2 g), or 1/2 tsp dried thyme (0.5 g)
1 bay leaf (about 0.2 g)
1 tsp Worcestershire sauce (5 ml), optional
4 thick slices French bread or baguette (about 200 g total)
1 1/2 cups grated Gruyère cheese (150 g)
1 tbsp chopped fresh parsley (4 g), optional, for serving

Instructions

Prepare the onions and toppings. Peel the onions, cut them in half through the root, and slice them thinly from top to bottom. Thin, even slices soften at a similar rate. Grate the Gruyère and measure the broth, wine, thyme, and bay leaf so they are ready when the onions finish cooking.
Caramelize the onions, 45 minutes. Melt the butter with the olive oil in a heavy Dutch oven or large, wide pot over medium heat. Add the onions and salt, and stir until coated. Cook uncovered, stirring every few minutes, until the onions have collapsed and become a deep golden brown, about 45 minutes. If they begin sticking or darkening too quickly, lower the heat and stir more often; add a tablespoon of water to loosen browned bits if needed. The color should develop gradually rather than turn black.
Deglaze the pot. Pour in the wine and scrape the bottom of the pot with a wooden spoon to release the flavorful browned onion bits. Simmer for about 2 minutes, until most of the sharp alcohol smell has faded. If you prefer not to use wine, use the same amount of broth here; the soup will taste a little less bright but will still be savory.
Simmer the soup, 20 minutes. Add the chicken broth, thyme, bay leaf, pepper, and Worcestershire sauce if using. Bring the soup just to a boil, then reduce the heat and simmer gently, uncovered, for 20 minutes. Remove the thyme stems and bay leaf. Taste the broth before adding more salt, since store-bought broth can vary considerably in saltiness.
Toast the bread, 4 minutes. While the soup simmers, toast the bread slices in a toaster or under a broiler, turning once, until dry and lightly browned on both sides. The slices should be sturdy enough to support the cheese without immediately dissolving into the soup. If using a broiler, watch closely because thin baguette slices can brown quickly.
Top the bowls. Set an oven rack a few inches below the broiler and heat the broiler. Ladle the hot soup into four broiler-safe bowls placed on a sturdy baking sheet. Put one slice of toast on each bowl and divide the Gruyère evenly over the bread, letting some cheese reach the edges. Leave space at the top of each bowl so the soup does not spill when moved.
Melt the cheese, about 3 minutes. Broil until the cheese is bubbling and browned in spots, usually 2 to 3 minutes. Keep the baking sheet in view; broilers vary, and the cheese can go from melted to scorched quickly. Use oven mitts to remove the very hot bowls and let them stand for a minute before serving. Finish with parsley if desired.

Tips

Give the onions time. The onions are the main source of this soup’s sweetness and depth. A crowded pot or overly high heat can steam them at first and burn them later. Use a wide, heavy pot, keep the heat around medium or medium-low, and judge by the onions’ deep golden color rather than by a strict timer. A few extra minutes are better than rushing them.
Choose broth thoughtfully. Low-sodium chicken broth gives you control over the final seasoning. Regular broth works, but wait until the soup has simmered before deciding whether it needs more salt. Homemade chicken stock is also suitable. Chicken broth makes a gentler, lighter soup than the beef broth often used in French onion soup; it will not taste exactly the same, but the browned onions, thyme, and Gruyère still make it full-bodied.
Use a sensible cheese substitute. Gruyère melts smoothly and has a nutty, savory flavor. If it is difficult to find, use Swiss cheese or Emmental, which are widely available and melt well, though their flavor is milder. A little grated Parmesan mixed with either cheese can add a sharper, saltier note. Avoid piling on too much cheese, which can become greasy and make the topping hard to eat.
Keep the bread from going soggy too soon. Toasting the bread first helps it hold its shape under the cheese. For a dinner where people may be eating at different times, keep the soup hot in the pot and assemble and broil each serving just before it is served. Do not put ordinary glass bowls under a broiler; use dishes explicitly labeled broiler-safe.

Serving Suggestions

Serve the soup as soon as the cheese has melted, while the bread is crisp at the edges and the broth is piping hot. The bowls retain heat, so set them on heatproof plates or trivets and warn everyone that they are hot. A small green salad with a sharp vinaigrette is a useful contrast to the sweet onions and rich cheese. A simple plate of sliced apples, pears, or crisp vegetables can also make a lighter accompaniment.

For a more substantial meal, serve one bowl per person with extra toasted bread on the side. If the soup is part of a larger menu, use smaller ovenproof bowls and serve it as a starter. A little chopped parsley adds freshness, but it is optional; avoid adding large amounts of garnish that would compete with the onion and cheese. Put extra cheese at the table if guests want a more generous topping.

Variations

Skip the wine: Replace it with an equal amount of chicken broth and deglaze as directed. A teaspoon of apple cider vinegar or lemon juice stirred into the finished soup can restore a touch of brightness, but add it gradually and taste as you go. The soup should remain savory rather than noticeably sour.

Make it vegetarian: Use vegetable broth in place of chicken broth and choose a vegetarian Worcestershire-style sauce, or omit the Worcestershire. Some Worcestershire sauces contain anchovies, so check the label if that matters for your meal. The result will have a different base flavor but still benefits from deeply browned onions and a good melting cheese.

Make it gluten-free: Use certified gluten-free broth and gluten-free bread, and check the Worcestershire label. Toast the bread until firm before topping the soup. If you cannot find suitable bread, serve the cheese separately on toasted gluten-free slices rather than placing an unsuitable crouton in the bowl.

Try another cheese blend: Use half Gruyère and half Emmental, Swiss, or low-moisture mozzarella. Mozzarella adds stretch but is milder, so combining it with a more flavorful cheese gives a better balance. Keep the total amount close to the recipe quantity so the topping melts evenly without forming a heavy layer.

Storage and Reheating

For the best texture, store the soup and the bread-and-cheese topping separately. Transfer leftover soup to a shallow covered container and refrigerate it within 2 hours of cooking; it keeps for 3 to 4 days. Store toasted bread at room temperature in a sealed container for a day, or toast fresh slices when serving. Refrigerated bread will soften, so refresh it in a toaster or a 350°F (175°C) oven until crisp.

Reheat the soup gently in a saucepan over medium-low heat, stirring occasionally, until steaming throughout. Add a splash of broth or water if it has reduced or tastes too concentrated. USDA FSIS guidance is to reheat leftovers to 165°F (74°C); check with a food thermometer if you need to verify the temperature. Ladle the hot soup into bowls, add fresh toast and cheese, and broil as directed. Freeze the soup without bread or cheese for up to 2 to 3 months for best quality. Thaw it in the refrigerator before reheating; the onion texture may soften slightly, but the flavor remains useful.

Frequently Asked Questions

Can I make French onion soup with chicken broth instead of beef broth?
Yes. Chicken broth gives the soup a lighter, less robust flavor than beef broth, but it works well with slowly caramelized onions, thyme, and Gruyère. Choose a flavorful, preferably low-sodium broth and taste after simmering so you can adjust the seasoning without making it too salty.

Why are my onions not turning brown?
They may need more time, or the pot may be crowded or too cool. Keep cooking and stir regularly, allowing moisture to evaporate before the onions begin to brown. If there is a lot of liquid in the bottom, continue uncovered. If the onions are sticking before they are golden, lower the heat and loosen the pot with a small splash of water rather than letting the fond burn.

Can I make the soup ahead?
Yes. Cook the soup through the simmering step, cool it promptly, and refrigerate it in a covered container for up to 3 to 4 days. Reheat to 165°F (74°C), then toast the bread, top the bowls with cheese, and broil just before serving. Keeping the topping separate preserves the bread’s texture and gives you the freshly melted finish.

What can I use if I do not have oven-safe soup bowls?
Do not put bowls under the broiler unless they are specifically labeled broiler-safe. Instead, place the toasted bread on a baking sheet, top it with cheese, and broil until melted and browned. Set one cheesy toast on each bowl of hot soup immediately before serving. The bread may float differently, but the flavor and practical result are very similar.

Is the wine necessary?
No. It adds acidity and helps lift the browned bits from the pot, but extra chicken broth works as a direct substitute. If the finished soup tastes a little flat without wine, add a small amount of lemon juice or cider vinegar, then taste again. Add it a few drops at a time so the broth does not become sharp.

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Safety notes: safe minimum internal temperatures from USDA FSIS; raw and undercooked fish guidance from the U.S. FDA. Food safety notes

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