Easy French Onion Soup
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This easy French onion soup is made with slowly caramelized onions, rich beef broth, fresh thyme, and a splash of white wine. Topped with toasted baguette and bubbling Gruyère cheese, it’s a classic French comfort food that’s surprisingly simple to make at home.
The secret is giving the onions time to develop their deep, golden sweetness. If you love cozy, comforting soups, try my creamy chicken and wild rice soup or Hungarian mushroom soup next.
Why this recipe works
Ingredients Required
- Yellow onions: The star of the soup. Slowly caramelizing them brings out their natural sweetness and creates a deep, rich flavor.
- Butter and olive oil: Help the onions soften and caramelize without burning, while adding richness to the soup.
- Garlic: Adds a subtle savory depth that complements the sweet onions.
- All-purpose flour: Lightly thickens the broth and gives the soup a little more body.
- Dry white wine: Deglazes the pan, lifting the flavorful browned bits and balancing the sweetness of the onions with acidity.
- Beef broth: Creates the rich, savory base of the soup. Use a good-quality broth for the best flavor.
- Fresh thyme and bay leaf: Add classic French aromatics without overpowering the onions.
- Baguette: Toasted slices provide a sturdy base for the melted cheese without becoming immediately soggy.
- Gruyère cheese: Melts beautifully and adds a rich, nutty flavor to the golden, bubbling topping.
See the recipe card at the bottom of the post for exact quantities and full instructions.
How to Make French Onion Soup
- Soften the onions. Melt the butter with the olive oil in a large, heavy-bottomed pot over medium heat. Add the thinly sliced onions and cook, stirring occasionally, until softened and translucent.
- Caramelize the onions. Continue cooking over medium-low heat, stirring regularly, until the onions turn a deep golden brown. This takes patience, but it’s what gives French onion soup its signature rich, sweet flavor. Reduce the heat if the onions begin to catch or burn.
- Build the broth. Stir in the garlic and flour, cooking briefly before adding the white wine. Scrape up any browned bits from the bottom of the pot, then add the beef broth, thyme, and bay leaf. Simmer gently to allow the flavors to develop.
- Add the cheesy topping. Ladle the soup into oven-safe bowls and top with toasted baguette slices and grated Gruyère. Place under the broiler until the cheese is melted, bubbling, and golden brown. Serve immediately.
Chef’s Guide: Expert Tips
Drawing on a decade of experience in Michelin-starred kitchens and Cordon Bleu training, I have compiled my top tips for recipe success.
- Slice the onions evenly: Thin, uniform slices cook at the same rate, giving you beautifully caramelized onions without some burning before others have softened.
- Don’t rush the caramelization: Cook the onions slowly over medium-low heat, stirring regularly. They should become deeply golden brown, soft, and sweet. This is where most of the soup’s flavor develops.
- Deglaze as needed: If browned bits begin sticking to the bottom of the pot, add a splash of water and scrape them up. This prevents burning while preserving all that delicious flavor.
- Use good-quality beef broth: With so few ingredients, the quality of the broth makes a noticeable difference. Choose one with a rich, savory flavor that isn’t overly salty.
- Toast the baguette first: Lightly toasting the bread helps it hold its shape beneath the soup and melted cheese instead of immediately becoming soggy.
- Broil just before serving: Add the baguette and Gruyère immediately before broiling, and watch closely. You want bubbling, golden cheese without burning the bread.
Storing & Reheating
- Fridge: Store leftover French onion soup in an airtight container in the refrigerator for up to 4 days. Keep the baguette and cheese separate to prevent them from becoming soggy.
- Freezer: Freeze the soup without the bread or cheese in freezer-safe containers for up to 3 months. Leave a little room for expansion.
- Reheating: Thaw overnight in the refrigerator if frozen, then gently reheat in a saucepan over medium heat until piping hot. Ladle into oven-safe bowls, top with freshly toasted baguette and Gruyère, and broil until golden and bubbling.
- Make-ahead tip: The soup base can be prepared 1–2 days in advance. The flavor often develops further as it sits, making this an excellent dish to prepare ahead and finish just before serving.
FAQs
Caramelizing onions typically takes 40–60 minutes, depending on the quantity, pan, and heat. Cook them slowly, stirring regularly, until they’re deeply golden brown, soft, and sweet. Rushing this step can leave the soup lacking its signature rich flavor.
Bitterness usually comes from onions that have burned rather than caramelized. Keep the heat at medium-low, stir regularly, and add a splash of water if the browned bits on the bottom of the pot start getting too dark.
Yes. Replace the white wine with an equal amount of beef broth and add a small splash of white wine vinegar or lemon juice for acidity. The flavor will be slightly different, but the soup will still be delicious.
Swiss cheese or Comté are excellent substitutes because they melt well and have a similar nutty flavor. Provolone also works if you prefer a milder cheese.
Easy French Onion Soup
Ingredients
- 6 cups (960 g) thinly sliced yellow onions
- 2 tablespoons butter
- 2 tablespoons olive oil
- 6 sprigs fresh thyme
- 1 bay leaf
- ½ cup (120 ml) dry white wine
- 4 cups (1 litre) beef broth
- 4 slices baguette, toasted
- 1½ cups (170 g) grated Gruyère cheese
- Salt and black pepper, to taste
Instructions
Caramelize the Onions
- Heat the butter and olive oil in a large, heavy-bottomed pot over medium heat.
- Add the sliced onions, thyme leaves (removed from their sprigs), and bay leaf. Stir to coat the onions in the butter and oil.
- Reduce the heat to low and cook for about 45 minutes, stirring occasionally at first and more frequently as the onions begin to brown. Season with salt and continue cooking until the onions are deeply golden brown, soft, and caramelized. If they begin to stick, add a splash of water and scrape up the browned bits.
Make the Soup
- Pour in the white wine, stirring to scrape up any browned bits from the bottom of the pot. Simmer for 2–3 minutes to reduce slightly.
- Add the beef broth and bring to a gentle boil. Reduce the heat and simmer for 20–30 minutes to allow the flavors to develop. Taste and adjust the seasoning with salt and black pepper.
Prepare the Topping
- Preheat the broiler. Ladle the soup into four oven-safe bowls and top each with a slice of toasted baguette.
- Divide the grated Gruyère evenly between the bowls, covering the bread generously.
Broil and Serve
- Place the bowls on a sturdy baking sheet and broil for 3–5 minutes, until the cheese is melted, bubbling, and golden brown. Watch closely to prevent burning.
- Garnish with additional fresh thyme, if desired, and serve immediately. Be careful, as the bowls will be very hot.
Notes
- For deeply caramelized onions: Cook slowly over low heat, stirring more frequently toward the end. If the onions begin to stick, add a splash of water to loosen the browned bits without burning them.
- For the best cheesy topping: Toast the baguette before adding it to the soup and use freshly grated Gruyère for smooth, even melting.
- Storing leftovers: Refrigerate the soup without the bread or cheese in an airtight container for up to 4 days, or freeze for up to 3 months. Reheat thoroughly and add the fresh toppings just before serving.
Nutrition
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Meet the Chef!
Hi, I’m Debs, a Cordon Bleu-trained chef and recipe developer. I help you get incredible dinners on the table fast with fool-proof recipes, step-by-step instructions, and tips and tricks I’ve learned over a 10-year career in professional kitchens.
Holy moly! This is a fantastic recipe! I doubled the onions and put 4 cloves of garlic in. But hey, it’s just who I am! The recipe on a whole is absolutely delicious!
So happy you loved this recipe! And thank you so much for taking the time to let me know. It’s very appreciated!
These make smaller servings, certainly not meant to be a meal but instead a side. I liked the flavor as is but my husband preferred more spices added, to each their own I guess. I’d make it again, but double it if you’re going to eat it as a main.
Delicious!
Thank you!
Labor of Love!🧅
So happy you loved this recipe! And thank you so much for taking the time to leave a comment. It’s so appreciated! 🙂
This is the best recipe. Have made it many times always delicious! We love it!
So happy you loved this soup. It’s perfect for a cold snowy day! 🙂
Delicious and so easy to make! I made a beef stock in my pressure cooker and everything turned out so good! Unfortunately, I do not have broiler safe crocks, so I had to first toast my bread. This was such an enjoyable recipe to make and eat, that I’m thinking of purchasing soup crocks now.
So happy you love this recipe so much! Broiler safe bowls will be so great! 🙂
Such a great recipe. We loved this one.
If it’s a little too sweet what should I do
You can try adding a splash of cider or wine vinegar to tone it down a little bit. You may have a very sweet batch of onions.
Delicious and easy. Comfort and elegance at the same time. Perfect combination.
this was delicious ! will make again thank you
Great recipe! Thank you.
Yummy so tasteful. I made with vegetable broth, im vegetarian and added a dash of Worcestershire sauce.
So happy this recipe was a hit! 🙂
This was delicious. I did add Worcestershire sauce and balsamic vinegar a splash of each. With a pinch of sugar. Yummy
So happy you loved the recipe. And thank you so much for taking the time to leave a comment and a rating. It is so appreciated! 🙂
As far as broth goes is any boxed broth acceptable? I look for one without many ingredients.
Thank you for the method you present with your recipes which allows for the least mistakes assuring good results.
Any boxed broth will do. So happy you love the recipe. 🙂
This looks awesome, Debs! Love those copper pots too.