Why You’ll Love This Recipe
French Onion Soup is a timeless classic that combines deeply caramelized onions, rich beef broth, and a golden, cheesy topping. Its savory, comforting flavor and rustic elegance make it ideal for cozy dinners or sophisticated starters. With just a few ingredients and a bit of patience, you’ll achieve a dish that’s hearty, flavorful, and undeniably satisfying.
ingredients
Tip: You’ll find the full list of ingredients and measurements in the recipe card below.
yellow onionsbutterolive oilbeef stock (or broth)white wine (optional)fresh thymebay leafgarlic clovesflour (for thickening)salt and pepperbaguette slicesgruyère cheese (or Swiss)
directions
Slice onions thinly and set aside.
In a large pot, melt butter with olive oil over medium heat. Add onions and cook slowly, stirring often, until deeply caramelized and golden brown—about 30-40 minutes.
Add minced garlic and cook for 1-2 minutes. Sprinkle with flour and stir to coat the onions.
Pour in white wine (if using) and let it simmer until reduced by half.
Add beef stock, thyme, bay leaf, salt, and pepper. Simmer uncovered for 30 minutes. Remove bay leaf and adjust seasoning.
Preheat broiler. Ladle soup into oven-safe bowls.
Top each with toasted baguette slices and a generous amount of grated gruyère cheese.
Broil for 2-4 minutes until cheese is melted and bubbling.
Servings and timing
This recipe yields approximately 4 servings.Preparation time: 15 minutesCaramelizing time: 35-40 minutesSimmering time: 30 minutesBroiling time: 4 minutesTotal time: 1 hour 30 minutes
Variations
Use chicken or vegetable broth for a lighter version.
Try red wine instead of white for a richer depth.
Swap gruyère with mozzarella, provolone, or fontina.
Add a splash of brandy or cognac for extra warmth.
storage/reheating
Store leftover soup (without the bread/cheese topping) in the fridge for up to 4 days.Reheat gently on the stove. Re-toast bread and re-broil with cheese before serving.Freeze soup base (without bread/cheese) for up to 3 months. Thaw and reheat as needed.
FAQs
Why do the onions take so long to caramelize?
Slow cooking brings out their natural sugars and deep flavor—rushing this step compromises the taste.
Can I make this vegetarian?
Yes, substitute beef broth with a rich vegetable broth.
Do I need oven-safe bowls?
Yes, for broiling the cheese directly on the soup. If unavailable, broil cheese on toast separately and place on soup before serving.
Can I use pre-grated cheese?
Pre-grated cheese works, but freshly grated melts better and offers more flavor.
What kind of onions work best?
Yellow onions are traditional, but white or sweet onions can also be used.
Can I prepare this in advance?
Absolutely! Make the soup base ahead, then broil the cheese topping when ready to serve.
Is this gluten-free?
Use gluten-free bread and flour alternatives to make it gluten-free.
Can I skip the flour?
Yes, though it helps slightly thicken the soup. It can be omitted or replaced with cornstarch.
Why is my soup too salty?
Taste the broth before seasoning. Some store-bought stocks are high in salt—use low-sodium when possible.
Can I make a large batch?
Yes, this recipe scales easily for bigger groups.
Conclusion
French Onion Soup is a deeply flavorful, soul-warming dish that turns humble ingredients into an elegant meal. Whether you’re serving it at a dinner party or enjoying a cozy night in, its rich broth, melty cheese, and golden toast make every bite unforgettable.
Print
French Onion Soup
- Prep Time: 15 minutes
- Cook Time: 45 minutes
- Total Time: 1 hour
- Yield: Serves 6–8
- Category: Soup
- Method: Simmering & Gratinée
- Cuisine: French
- Diet: Vegetarian
Description
A savory and comforting French onion soup made with slowly caramelized onions in a rich broth, topped with toasted baguette slices and melted Gruyère cheese.
Ingredients
- 50 g butter
- 1 tbsp olive oil
- 6 large white onions, thinly sliced
- 1½ tbsp caster sugar
- 200 ml dry white wine
- 2 litres beef or vegetable stock
- 3 bay leaves
- 1 sprig rosemary
- Salt and freshly ground black pepper
- ½ baguette
- Dijon mustard, for spreading
- 25 g Gruyère cheese, grated
Instructions
- Heat butter and oil in a large saucepan. Add onions and cook over high heat for 2–3 minutes, then cover and reduce heat. Cook for 10 minutes until softened.
- Remove lid, add sugar, salt, and pepper. Cook uncovered for 15 minutes, stirring occasionally, until onions are deep golden and caramelized.
- Preheat grill to medium-high. Add wine to the onions and boil for 2–3 minutes.
- Add stock, bay leaves, and rosemary. Bring to a boil, then simmer for 10 minutes. Remove herbs and adjust seasoning.
- Slice baguette and toast one side under the grill. Spread the untoasted side with mustard, top with Gruyère, and grill until melted.
- Ladle soup into bowls and top each with a cheesy crouton. Serve hot.
Notes
- Can be made up to 4 days in advance and reheated.
- Croutons can be prepared ahead and grilled before serving.
- For a vegetarian version, use vegetable stock.
- Caramelizing the onions thoroughly is key to flavor.