If you’re craving a warm, comforting dish that’s bursting with flavor, look no further than this French Onion Soup recipe. This timeless French bistro classic is loved for its rich caramelized onions, savory broth and bubbly, cheesy topping.

And the best part? You don’t have to be a professional chef to make it at home! With simple ingredients and a little patience, you can enjoy an authentic bowl of French Onion Soup in the comfort of your own home.

My recipe for a traditional French onion soup

French onion soup is a beloved classic, and while there are many variations, mine stays true to tradition. I’m not suggesting that other recipes aren’t delicious, but as you know, my passion for rustic, authentic French cuisine drives me to offer you classic takes on timeless dishes.

Making a great French onion soup is about developing deep flavors, balancing the sweetness of caramelized onions with the savory richness of beef broth, and creating a perfect, melty cheese topping.

I start by slowly caramelizing the onions in butter, without adding sugar. Unlike some recipes—such as Julia Child’s—I find that sugar makes the onions overly sweet, which can throw off the balance of flavors. If my onions happen to be difficult to caramelize, I sometimes add a splash of balsamic vinegar. But the key here really is patience – a low, slow cooking will yield the best caramelization.

For the broth, I rely on a traditional blend of red wine and beef stock, which creates a rich and complex flavor profile. While some modern recipes use white wine or chicken/vegetable broth, I believe beef broth paired with red wine provides the best depth and complexity.

In keeping with tradition, I also steer clear of non-traditional seasonings like fish sauce or Worcestershire sauce.

The only slight twist in my version is in the bread topping: instead of the typical large slice of bread, I use homemade croûtons—cubed, toasted bread—which makes the soup easier to eat without sacrificing flavor or texture.

Key Ingredients for French Onion Soup

For this traditional French Onion Soup, you’ll need the following ingredients:

• • Onions: For 4 people, you’ll need 4 large (or 5 medium) onions, thinly sliced. Yellow onions are the classic choice, but for a milder flavor, you can mix in some sweet onions or even red onions.
  • Garlic: 2 cloves, minced for added depth.
  • Butter: 3 tablespoons of (unsalted) butter to help caramelize the onions.
  • Beef Broth: 8 cups (2L) of good-quality beef broth for a rich, savory base. If you don’t have homemade beef stock, choose a good-quality store-bought beef stock, ideally low-sodium.
  • Red Wine: 1 cup (250ml) red wine to deglaze the pot and enhance the depth of flavor.
  • Fresh Thyme: A few sprigs of fresh thyme or 1 teaspoon dried thyme for a touch of herbal flavor.
  • Salt and Pepper: Season to taste.
  • Baguette: Thick slices of day-old French baguette, cubed and toasted.
  • Olive Oil : to help crisp up the bread cubes. 
  • Gruyère Cheese: 1 cup (100g) shredded Gruyère, or a combination of Gruyère and Swiss cheese, for the irresistible melted topping.

As for the equipment, a large high-edge skillet works well for caramelizing the onions. You will also need individual oven-safe soup bowls to do the best part of this recipe – broiling the Gruyère cheese on top until golden and bubbly!

Step-by-Step Instructions: How to Make Classic French Onion Soup

1. Caramelize the Onions: For the perfect French onion soup, slowly cook thinly sliced onions and garlic in butter for 40-60 minutes until golden and caramelized. Don’t rush! This step releases the onions’ natural sweetness. I like mine on the lighter side, but you can go a touch darker. 
2. Deglaze the Pot: Once caramelized, pour in the red wine, scraping up any bits from the pot. Simmer until the wine reduces by half to enhance the flavor.
3. Add Broth and Herbs: Add beef broth and thyme. Bring to a boil, then simmer uncovered for 1 hour. Season with salt and pepper to taste.
4. Make croûtons: Cube and toss the bread with olive oil. Toast the cubes under the broiler until crisp and golden.
5. Assemble and Broil: Ladle soup into bowls, top with croutons, and cover with Gruyère cheese. Broil until the cheese is melted and bubbly.
6. Serve and Enjoy! Carefully remove from the oven, garnish with thyme, and serve hot. Enjoy this satisfying French onion soup on its own or with a salad!

10 Pro Tips for the Best French Onion Soup

I’ve ordered lots (lots!) of French Onion soups in restaurants and I’ve spent years perfecting my French onion soup recipe in my kitchen. I am sharing here my best tips that will help you make a deeply flavorful and comforting bowl that’s absolutely restaurant-worthy! 

1. Caramelize Slowly: Cook onions over low to medium heat for 40–60 minutes, stirring occasionally – about every 5 minutes, until they turn golden. Caramelized onions can’t be done in 20 or 30 minutes: do not rush this process! Patience is key for developing the rich flavor that defines French Onion Soup.

2. Don’t Over-Darken: Caramelize the onions until they reach a rich golden-brown color, but avoid going too dark. Many people think caramelized onions should be deep brown, but that can lead to bitterness. In my experience, stopping at a light to rich golden-brown stage gives you the perfect balance of sweetness and depth of flavor, without any bitterness.

3. Use a Wide, Heavy Pan: A wide, heavy-bottomed pan helps the onions cook evenly and prevents them from steaming.

4. Add Balsamic Vinegar: If your onions lack sweetness or are having issues caramelizing, add a splash of balsamic vinegar! I prefer balsamic vinegar to sugar: this helps with caramelization, without making the soup too sweet.

5. Deglaze with Red Wine: After caramelizing, deglaze the pan with red wine, scraping up the flavorful bits from the bottom with a wooden spoon. Then, simmer until the wine reduces by at least half, to cook off the alcohol and to avoid bitterness.

6. High-Quality Beef Broth: Use beef broth—preferably homemade or a good-quality store-bought one. It should be rich and deeply flavoured. Some recipes call for chicken broth, but I honestly think it doesn’t deliver the same richness and complexity as beef broth.

7. Simmer for an Hour: Once the broth is added, simmer the soup for at least one hour to meld the flavors. I know this takes times, but the longer the simmering, the richer the taste!

8. Use Sturdy, Toasted Bread: Thick cubes of day-old crusty baguette or country bread work best. Lightly toast them before adding to the soup to prevent them from getting soggy.

9. Gruyère Cheese: Use Gruyère or a mix of Gruyère and Emmental for the cheese topping. Gruyère melts beautifully and has a nutty flavor that complements the soup. In my opinion, parmesan (too salty) or mozzarella (to neutral) won’t deliver the same signature flavor.

10. Generous Cheese Topping: Place the toasted bread cubes on the soup and cover them with a generous amount of cheese before broiling for a bubbly, golden crust. 1/4 cup of cheese per bowl works for me, but feel free to add more!

Frequently Asked Questions

What is the best cheese for French Onion Soup?

Gruyère is the most common choice due to its nutty, smooth melting qualities. However, if you can’t find Gruyère, Swiss cheese, Emmental, or even mozzarella (as a last resort) will work well.

What is the best wine for French Onion Soup?

A dry red wine works best for making a French Onion Soup. My best recommendation is a Pinot Noir which is on the lighter side. If you want a richer taste with more kick, opt for a Cabernet Sauvignon.
Don’t use a cooking wine! Splurging a little to buy a drinking wine makes a big difference here.

Can I make French Onion Soup in advance?

Yes! This soup actually gets better the next day as the flavors continue to develop. Simply reheat on the stovetop and add the baguette and cheese just before serving.

Can I freeze French Onion Soup?

Absolutely! You can freeze the soup without the bread and cheese in an airtight container for up to 3 months. When ready to serve, thaw in the refrigerator, reheat, and proceed with the baguette and cheese topping.

Helpful Swaps:

• Onions variety: Yellow onions are the classic choice, but for a milder flavor, you can mix in some sweet onions or even red onions. The red onions tend to turn grey-ish when they cook, but the taste is still delicious!
• Cheese Options: Gruyère melts beautifully and has a nutty flavor that complements the soup. While Gruyère is traditional, you can substitute with Swiss, Emmental, or even a mix of Parmesan and mozzarella (if you have none of the other options) for a different twist.
• Make it Vegetarian: Swap out the beef broth for vegetable broth for a delicious vegetarian French Onion Soup option. The broth will be slightly less complex and less deep in flavor (in my opinion), but still delicious.

Gooey, crunchy, savory, comforting, succulent – there’s so many reasons to love French Onion soup! I hope you’ll enjoy this recipe as much as I do. If you have any questions, please leave a comment. 

More French Soups to try: 

• French Cabbage and Sausage Soup (Soupe Paysanne)
• Classic French Lentil Soup 
• Creamy Roasted Cauliflower Soup 
• Classic French Carrot Soup (Soupe Crécy)
• Provençal Garlic Soup (Aïgo Boulido)
• Watercress Soup (Soupe de Cresson)
• Split Pea Bacon Soup (Potage Saint Germain)
• Smoked Ham Hock Bean Cabbage Soup (Garbure)
• Creamy Leek and Potato Soup (Soupe Vichyssoise)

French Onion Soup

Print Recipe

Serves: 4 Prep Time: 15 Minutes Cooking Time: 2 Hours 2 Hours

Nutrition facts: 200 calories 20 grams fat

Rating: 4.0/5

( 5 voted )

Ingredients

3 tbsp (42g) butter
4 large yellow onions, peeled and sliced thinly in half rounds
2 garlic cloves, peeled and minced
¼ tsp salt
8 cups (2L) beef broth
1 cup (250ml) red wine
3-4 sprigs fresh thyme
½ tsp freshly ground black pepper
200g day-old baguette (or country bread)
3 tbsp (45ml) extra virgin olive oil
¼ tsp salt
¼ tsp black pepper
1 cup (100g) Gruyère cheese, grated

Instructions

1. Caramelize the onions: Place 2 tablespoons (28g) of butter is a large heavy-bottom pan over medium-low heat. Add the thinly sliced onions, garlic and salt and gently cook, stirring every 5-10 minutes until golden and caramelized. Don’t rush this step, it can take from 40 to 60 minutes for the onions to fully caramelize. Add 1 tbsp (14g) of butter halfway to help caramelization.
2. Deglaze: Once caramelized, pour in the red wine and scrape up any bits at the bottom of the pot with a wooden spoon. Turn the heat up to medium, and simmer until the wine reduces by half.
3. Add the beef broth, black pepper and thyme. Bring to a slow boil, turn the heat down to medium-low, and simmer uncovered for 1 hour. Taste and season with salt and pepper to taste.

Meanwhile, pre-heat your oven to 350°F (180°C) with a rack in the middle. Line a baking sheet with foil.

4. Make the croûtons: Cube the bread in ½-inch cubes and toss in a bowl with the olive oil, salt and pepper. Spread the bread cubes evenly onto the prepared baking sheet. Bake for 10 to 13 minutes, until crisp. Remove and transfer onto a cooling rack.
5. Discard of the thyme sprigs and ladle the soup into bowls.
6. Assemble and broil: When ready to serve, set your oven to broil. Top each (oven safe) soup bowl with croûtons, and cover with ¼ cup (25g) Gruyère cheese. Broil in the oven until the cheese is melted and bubbly. Keep an eye on it, broiling takes 1 to 2 minutes at most. Serve hot.