French onion soup is a classic dish that’s deeply comforting and rich in flavour. It’s made by slowly caramelising onions until golden brown, then simmering them in beef broth with herbs like thyme and bay leaf. The soup is finished with a crusty slice of baguette topped with melted cheese — usually Gruyère — broiled to golden perfection.
This warm, savoury soup is perfect for chilly days or cosy nights. It combines sweet, soft onions with salty broth and crunchy, cheesy bread, creating a balance that’s hard to resist. It’s simple but feels gourmet, making it a popular choice for both home cooks and restaurant menus.
Cooking French onion soup is always satisfying, especially when the onions hit that perfect caramel shade and fill the kitchen with their sweet aroma. There’s a rhythm to the slow cooking, where patience rewards you with incredible depth of flavour. Adding the bread and watching the cheese bubble and brown in the oven feels like the final magic touch.
Why You’ll Love This French Onion Soup Recipe
This French onion soup is comfort in a bowl. With rich, slow-cooked onions and savoury beef broth, every spoonful feels warm and cosy. It’s a hug for your taste buds.
You’ll love the cheesy topping. Melted Gruyère over crispy bread adds the perfect crunch and creaminess. Each bite is packed with bold, classic French flavour.
It’s surprisingly easy to make. You don’t need fancy ingredients—just onions, broth, bread, and cheese. Simple steps give you a restaurant-worthy dish at home.
This recipe works for any time. Serve it for lunch, dinner, or as a starter at gatherings. French onion soup brings warmth and joy to every occasion.
Pre-preparation of French Onion Soup
Before you begin cooking, take a few minutes to prep everything. Here’s what that looks like:
- Peel and thinly slice six large yellow onions. They’re the star of this soup, so go for fresh, firm ones.
- Grate your cheese — Gruyère is traditional, but you can blend it with mozzarella or Swiss for a softer texture.
- Cut your baguette into thick slices and leave them out to stale slightly, or toast them lightly. They’ll hold up better in the soup.
- Warm your beef broth on the side. Using warm stock prevents the onions from cooling too quickly when added.
How to Make French Onion Soup Recipe
Ingredients
Here’s everything you’ll need to bring the soup to life:
- 6 large yellow onions, thinly sliced
- 3 tablespoons unsalted butter
- 1 tablespoon olive oil
- 2 garlic cloves, minced
- 1 tablespoon all-purpose flour (optional, helps thicken)
- 1/2 cup dry white wine (or cooking wine)
- 8 cups beef broth (low-sodium recommended)
- 1 tablespoon balsamic vinegar (optional, for depth)
- 1 teaspoon sugar (helps caramelisation)
- Salt and freshly ground black pepper, to taste
- 1 French baguette, sliced
- 2 cups grated Gruyère cheese
Directions
- Melt butter and oil in a heavy-bottomed pot over medium-low heat.
- Add onions and sugar, stir to coat. Cook slowly for 40–45 minutes, stirring often, until they’re deep golden brown.
- Add garlic, stir for 1 minute. Sprinkle flour (if using) and stir another minute.
- Deglaze with wine. Scrape up the fond (the brown bits) for flavour.
- Add warm beef broth, balsamic vinegar (if using), salt, pepper, and herbs.
- Simmer for 25 minutes, partially covered. Discard herbs if added.
- Toast the baguette slices while the soup simmers.
- Preheat broiler. Place soup into oven-safe bowls, top each with a toast slice and plenty of cheese.
- Broil until cheese is golden and bubbly, about 2–3 minutes.
Nutrition and Health Benefits of French Onion Soup
French onion soup is a flavorful, warming dish made with caramelised onions, broth (usually beef or vegetable), herbs, and topped with bread and melted cheese. While it’s often considered comfort food, it also comes with real nutritional value and health benefits. Below are the key points to understand the nutrition and health benefits of French onion soup:
Nutritional Benefits:
- Rich in Antioxidants: Onions are high in flavonoids, especially quercetin, a powerful antioxidant that helps fight cell damage and inflammation.
- Good Source of Fibre: Onions contain dietary fiber that supports digestion, helps control blood sugar, and keeps you full longer.
- Low in Calories (without excess cheese or bread): A basic French onion soup (without too much cheese or thick bread) is low in calories, making it suitable for light meals or weight-conscious diets.
- Contains Vitamins and Minerals: Onions provide Vitamin C, B6, and folate. The soup also includes minerals like potassium, calcium, and magnesium, depending on the stock used.
- Protein from Broth and Cheese: When made with beef broth and cheese, the soup adds a small but helpful amount of protein to the diet.
- Hydrating and Warm: Being a soup, it contributes to fluid intake and can be soothing during cold seasons.
- Calcium-Rich (if topped with cheese): Cheese adds calcium which supports bone health, especially helpful for growing children and ageing adults.
Health Benefits:
- Supports Heart Health: Onions have compounds that lower cholesterol and improve blood pressure. This may reduce the risk of heart disease.
- Boosts Immunity: The Vitamin C and phytochemicals in onions help strengthen the immune system and fight infections.
- Anti-Inflammatory Properties: Quercetin in onions can help reduce inflammation in the body, supporting joint and overall wellness.
- May Help Regulate Blood Sugar: Onions may support healthy blood sugar levels, making the soup a good option for people managing diabetes (when eaten without white bread).
- Promotes Gut Health: The fiber in onions feeds good bacteria in the gut, helping digestion and improving nutrient absorption.
- Can Relieve Cold Symptoms: Warm broth can ease sore throats and nasal congestion, and onions have mild expectorant properties.
- Mood Boosting Effects: The comforting warmth and aroma of the soup, along with its nutritional value, can naturally improve mood and reduce stress.
French Onion Soup Variation
There are many ways to make French onion soup your own. You can switch the beef broth with vegetable broth for a vegetarian version. Add a splash of wine, such as white or red, to deepen the flavour. Some recipes use shallots for a sweeter taste, or a mix of different onions. For cheese, Gruyère is the traditional choice, but Swiss or mozzarella also work well. You can even bake the soup in individual bowls for a more restaurant-style feel.
How to Serve French Onion Soup
Serve French onion soup hot and fresh in oven-safe bowls. Place a slice of toasted baguette on top and layer with shredded cheese. Then, broil until the cheese is bubbly and golden. This gives the soup a rich, crispy top with a gooey, cheesy texture underneath.
This soup pairs well with a fresh green salad or a simple glass of dry red wine. It also works as a starter before a heavier main dish. The bold onion flavour and cheesy topping make it a crowd-pleaser, especially in cold weather or on special occasions.
Storage Options
French onion soup stores well in the fridge for up to 4 days. Keep the soup and bread separate. Reheat the soup in a pot and toast the bread fresh before adding cheese and broiling. This keeps the texture crisp and the flavor fresh.
You can also freeze the soup (without bread or cheese) for up to 2 months. Use freezer-safe containers and leave space at the top. When ready, thaw in the fridge overnight and reheat. Add fresh toast and cheese to enhance the overall experience.
FAQs About French Onion Soup
What kind of cheese is best for French onion soup?
Gruyère cheese is the most traditional choice. It melts well and gives the soup a rich, savoury flavour.
Can I make French onion soup vegetarian?
Yes, just use vegetable broth instead of beef broth. The flavour will still be deep and delicious.
How do I get the onions perfectly caramelised?
Simmer them over low heat for 30–45 minutes. Stir often so they don’t burn and turn a rich golden brown.
Can French onion soup be frozen?
Yes, you can freeze the soup without the bread and cheese topping. Reheat and add fresh bread and cheese before serving.