French Images are for illustrative purposes only, may be inaccurate, and do not guarantee the presence or absence of specific ingredients. 
Serving Images are for illustrative purposes only, may be inaccurate, and do not guarantee the presence or absence of specific ingredients. Soupe à l'Oignon
Slowly caramelized onions melt into a rich beef broth, crowned with crusty bread and bubbling Gruyère — France's most comforting bowl.
Contains common allergens
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Instructions
5 steps- 1
Melt butter in a heavy-bottomed Dutch oven over medium heat. Add the sliced onions and cook, stirring occasionally, until deeply caramelized and jammy (about 40 minutes).
- 2
Deglaze the pot with a splash of dry white wine or beef broth, scraping up the browned bits from the bottom.
- 3
Pour in the remaining beef broth, add the fresh thyme, and bring to a gentle simmer. Cover and cook for 20 minutes to meld the flavors.
- 4
Preheat the broiler. Ladle the soup into oven-safe bowls, place a toasted slice of baguette on top of each, and cover generously with grated Gruyère cheese.
- 5
Broil for 3-5 minutes until the cheese is bubbling, melted, and golden brown with crispy edges. Serve immediately.
Images are for illustrative purposes only, may be inaccurate, and do not guarantee the presence or absence of specific ingredients. Listahan Family Score™
75/100
Good fit for most families
Score reflects how well this recipe fits a typical busy household. In the app, your Family Score is personalized to your household's allergens, kids, and pantry.
Nutrition
per serving275
Calories
14 g
Protein
14 g
Carbs
19 g
Fat
Estimated per serving. Actual values depend on the brands and portions you use.
Listahan cooking guide
Chef notes & practical guide
Technique notes, ingredient swaps, serve-alongside ideas, storage guidance, and equipment for this recipe.
Cultural context
Soupe à l'oignon — French onion soup in its broiled, cheese-topped form — is closely tied to the old Les Halles market district in Paris, where the soup was served through the early morning hours to workers finishing overnight shifts, even though onion-and-broth soups in France go back well before that specific association took hold.
Listahan note
This version caramelizes the onions the full stretch of time rather than rushing them with higher heat, since that slow step, not the broth, is what actually builds the soup's depth.
Technique cues
- Cooking the sliced onions low and slow, around 40 minutes, until they turn deeply jammy and browned builds most of the soup's flavor; rushing this stage with high heat browns the onions unevenly and leaves some tasting raw.
- Deglazing the pot with a splash of wine or broth after the onions caramelize lifts the browned bits stuck to the bottom, folding that concentrated flavor back into the soup instead of leaving it stuck to the pan.
- Gruyere is chosen specifically for how it melts, developing a stretchy, browned crust under the broiler rather than breaking into an oily puddle the way some cheeses do.
- The broiling step needs close watching rather than a set timer, since the cheese moves from bubbled and browned to burnt within a minute once it starts coloring.
Kitchen flow
- Parallel prep
- Prep dips or garnishes for Soupe à l'Oignon while the main component cooks or chills, so everything lands on the platter at once. This one leans on the thick slices rustic baguette. The simmer step is what sets the pace here.
- Make-ahead
- Soupe à l'Oignon can be assembled a few hours ahead and held, covered, until serving. This one leans on the thick slices rustic baguette. Everything else is quick — the simmer is the one step that takes real time.
- Leftover move
- Leftover Soupe à l'Oignon reheats best in an oven or air fryer rather than a microwave, which keeps it from turning soft. This one leans on the thick slices rustic baguette. Plan around the simmer; that's the slow part.
- Cleanup rhythm
- Wash serving dishes for Soupe à l'Oignon promptly if they held dips or sauces, which dry into a harder film than most other foods. This one leans on the thick slices rustic baguette. The simmer step is what sets the pace here.
Ingredient brief
Role, handling, and swap guidance for each key ingredient.
4 large yellow onions
Aromatic base
Purpose: large yellow onions creates the savory foundation before stronger ingredients are added.
Handling: Wash, trim, and cut evenly so the pieces cook at the same pace.
Adaptation: Use the closest fresh equivalent and expect a modest shift in flavor or texture.
6 cups rich beef broth
Main protein or body
Purpose: cups rich beef broth gives Soupe à l'Oignon its main substance and carries the seasoning.
Handling: Pat dry, cut evenly, and season before cooking so browning or sauce coverage is consistent.
Adaptation: Use the closest fresh equivalent and expect a modest shift in flavor or texture.
1 cup Gruyère cheese
Main protein or body
Purpose: cup Gruyère cheese gives Soupe à l'Oignon its main substance and carries the seasoning.
Handling: Prep before heat is high so the cooking step can move without rushing.
Adaptation: Use unsweetened dairy-free alternatives only where they still provide enough fat and body.
4 thick slices rustic baguette
Flavor support
Purpose: thick slices rustic baguette supports the balance of Soupe à l'Oignon and should taste integrated.
Handling: Prep before heat is high so the cooking step can move without rushing.
Adaptation: Use the closest fresh equivalent and expect a modest shift in flavor or texture.
3 tbsp unsalted butter
Richness and texture
Purpose: tbsp unsalted butter rounds the texture and helps the dish feel complete.
Handling: Prep before heat is high so the cooking step can move without rushing.
Adaptation: Use unsweetened dairy-free alternatives only where they still provide enough fat and body.
Technique notes
- Toasting the baguette slices before floating them on the soup keeps them from turning to mush the instant they hit the hot broth.
- Oven-safe bowls are worth using specifically for this soup, since the cheese-and-bread topping needs to go under the broiler as one unit.
- The soup base, without its bread and cheese topping, freezes well, making it practical to make ahead and finish fresh only at serving time.
Ingredient swaps
- Dairy-free direction
- Swap the unsalted butter for a neutral dairy-free butter or oil and a full-fat plant milk (oat or coconut work best for body) — the texture shifts slightly but the dish holds together. This one leans on the rich beef broth.
- Lower-sodium direction
- Use a low-sodium or no-salt-added version of the rich beef broth, then season to taste with fresh herbs, citrus, or vinegar at the end instead of more salt.
- Weeknight shortcut
- For a faster version, prep the longest-cooking component a day ahead so the night-of cook is mostly assembly and finishing. This one leans on the rich beef broth.
Serve alongside
- Steamed rice
- Cucumber salad
- Roasted vegetables
- Pickled vegetables
- Iced tea
- Sparkling water with citrus
Serving suggestions only — check pairings for your household's allergens.
Storage & reheating
- Refrigerate in a sealed container for up to 4 days.
- Reheat gently with a splash of water, broth, milk, or sauce as appropriate.
- Freeze up to 2 months when the texture is braised, baked, or stew-like.
Equipment
- Dutch oven or soup pot
- Wooden spoon
- Ladle
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