French Onion Soup Recipe
This French Onion Soup Recipe is one of the most iconic and beloved soups in the world. The extraordinary depth of flavor comes from one deceptively simple process. Specifically, it involves slowly caramelizing a large pile of onions until they transform into something dark, sweet and deeply complex. Moreover, this French Onion Soup Recipe is then topped with toasted baguette and bubbling melted Gruyere cheese for that irresistible finishing touch.
Additionally, once you make this at home you will be amazed at how achievable restaurant quality French Onion Soup truly is. Therefore, do not be put off by the caramelizing time. For more warming soups, explore our Tomato Soup Recipe, our hearty Beef Stew Recipe and our full Soup and Stew collection.
The Secret to This French Onion Soup Recipe
The entire soul of this French Onion Soup Recipe lives in the caramelized onions. This step cannot be rushed. It takes 35 to 40 minutes of patient cooking over medium low heat. The onions start out sharp, pungent and pale. However, with time and gentle heat they transform completely. Consequently, they turn deep golden brown, soft, silky and extraordinarily sweet.
Furthermore, as the onions caramelize their natural sugars develop through a process called the Maillard reaction. As a result, hundreds of new flavor compounds form in the pan. These compounds are what give this French Onion Soup Recipe its signature deep and complex taste. Moreover, it is this transformation that makes French Onion Soup so completely unlike any other soup in the world.
Which Onions to Use in This Recipe
The choice of onion matters significantly in this French Onion Soup Recipe. Therefore, it is worth selecting carefully. Here are the best options:
- Yellow onions — The most traditional choice. They have the perfect balance of sharpness and natural sugar for caramelizing. Moreover, they are widely available and affordable.
- White onions — Slightly sharper raw but they caramelize beautifully. Furthermore, they produce a cleaner and slightly sweeter finished flavor than yellow onions.
- Sweet onions (Vidalia) — Their higher sugar content means they caramelize a little faster. Additionally, they produce an even sweeter and more mellow finished soup.
- Red onions — Not traditional but they work well. Consequently, they give the soup a slightly richer and earthier flavor with a beautiful deep color.
The Best Cheese for the Topping
The cheese topping is what makes this French Onion Soup Recipe so visually spectacular. Moreover, the right cheese must melt smoothly and develop a golden crust under the broiler. Here are the best options:
- Gruyere — The most classic and highly recommended choice. It melts perfectly and adds a rich, nutty flavor. Furthermore, it is inseparable from truly authentic French Onion Soup.
- Emmental — A close relative of Gruyere. It melts equally well and has a milder, sweeter flavor. Additionally, it is often easier to find and more affordable.
- Provolone — An excellent melting cheese with a mild, slightly sharp flavor. Moreover, it browns beautifully under the broiler and works well when Gruyere is unavailable.
- Mozzarella with Parmesan — Mozzarella provides the melt and stretch. On the other hand, Parmesan adds sharp, salty depth. Together, they make a very accessible and delicious alternative.
The Role of Wine and Stock
After the onions are fully caramelized, a pour of dry white wine deglazes the pan. It lifts all the caramelized bits from the bottom. Moreover, the wine adds acidity and complexity that balances the sweetness of the onions. As a result, the broth tastes layered and interesting rather than one dimensionally sweet.
Furthermore, good quality beef stock is essential for this French Onion Soup Recipe. It provides the rich and savory backdrop the caramelized onions need to truly shine. On the other hand, a weak or watery stock produces a flat and disappointing broth. Consequently, always choose the best stock you can find.
How to Make This French Onion Soup Recipe
The process has three stages. First, slowly caramelize the onions with patience. Then, build and simmer the broth. Finally, ladle into oven safe bowls, top with toasted baguette and cheese and broil until golden and bubbling. The full method is in the recipe card below.
What to Serve with French Onion Soup
This French Onion Soup Recipe is a complete meal on its own with the bread and cheese topping. However, these light accompaniments pair beautifully alongside:
- A simple green salad with sharp Dijon mustard vinaigrette for a clean and refreshing contrast
- Extra sliced baguette on the side — moreover, it is perfect for mopping up the rich broth
- Our fresh and vibrant Greek Salad as a light starter before the soup
- Our crispy Garlic Bread Bites alongside for an extra indulgent bread option
- A glass of the same dry white wine used in the recipe — consequently, it creates a perfectly paired and elegant dining experience
How to Store This French Onion Soup Recipe
Store the broth and onion base in an airtight container in the refrigerator for up to 4 days. Reheat gently on the stovetop over medium heat. Moreover, the soup base freezes well for up to 3 months. Therefore, it is an excellent recipe for batch cooking ahead of the week.
Adding the Cheese Topping After Storage
Always prepare the cheese topping fresh just before serving. Do not add the bread and cheese before storing. The bread becomes completely sodden and the cheese loses its texture. Therefore, reheat the soup base first. Then add the fresh topping under the broiler immediately before serving for the best result.
Vegetarian French Onion Soup — Replace the beef stock with a rich vegetable stock. Additionally, add a tablespoon of soy sauce for extra umami depth to compensate for the absence of beef flavor.
Sherry Version — Replace the white wine with dry sherry for a nuttier, more complex and deeply traditional flavor that is widely used in classic French bistro versions.
Extra Cheesy — Use two layers of toasted baguette in each bowl with cheese between the layers and on top. As a result, every spoonful comes with an extraordinary amount of melted cheese.
Slow Cooker — Caramelize the onions on the stovetop first. Then transfer to a slow cooker with the stock and wine. Cook on low for 6 to 8 hours for a deeply flavored, hands off version.
Make This French Onion Soup Recipe Tonight
In conclusion, this French Onion Soup Recipe is one of the most impressive and deeply satisfying soups you can make at home. Therefore, whether you are hosting dinner guests or simply treating yourself to something truly special on a cold evening, this recipe always delivers. Browse more of our Soup and Stew recipes and share your results in the comments below!
French Onion Soup Recipe
Deeply caramelized sweet onions in a rich savory broth topped with toasted baguette and golden bubbling Gruyere cheese. A timeless bistro classic.
Ingredients
- The Caramelized Onions
- 1.2 kgYellow onions, thinly slicedThey reduce dramatically during caramelization. This large quantity is essential
- 3 tbspUnsalted butter
- 1 tbspOlive oil
- 1 tspSaltAdded at the start to draw moisture from the onions and speed up caramelization
- 1 tspCaster sugar (optional)Aids caramelization and enhances the natural sweetness of the onions
- The Broth
- 150 mlDry white wine (Sauvignon Blanc or Pinot Grigio)For alcohol free, use extra stock plus 1 tbsp white wine vinegar
- 1 litreGood quality beef stockThe backbone of the soup. Use the best quality stock you can find
- 1 tbspWorcestershire sauce
- 2 sprigsFresh thyme
- 1Bay leaf
- ½ tspBlack pepper, freshly cracked
- The Topping
- 8 thickSlices of baguette, toastedToast until very dry and crispy so they hold up in the hot soup without dissolving
- 200 gGruyere cheese, freshly gratedAlways grate fresh. Pre shredded cheese does not melt as smoothly or brown as beautifully
Equipment
Method for This French Onion Soup Recipe
- 1 Slice the onions: Peel and halve all the onions. Slice them thinly and as evenly as possible, approximately 3 to 4mm thick. Even slicing ensures the onions cook at the same rate. Uneven pieces result in some burning while others are still raw and underdeveloped.
- 2 Begin caramelizing: Melt the butter and olive oil together in a large heavy pot over medium heat. Add all the sliced onions and the salt. Stir to coat in the fat. Cook over medium heat for 10 minutes, stirring occasionally. The onions will first soften and become translucent. They will look like far too many to fit in the pot. However, they reduce dramatically as moisture evaporates.
- 3 Continue caramelizing slowly: Reduce the heat to medium low. Continue cooking for a further 25 to 30 minutes, stirring every 3 to 4 minutes. The onions will gradually turn golden, then light brown, then deep amber. If they stick to the bottom, add a tablespoon of water and scrape up the sticky bits. These bits are pure concentrated flavor. Do not discard them.
- 4 Deglaze with wine: Once the onions are deep golden brown and smell wonderfully sweet, pour in the white wine. It will sizzle dramatically. Stir vigorously to scrape every caramelized bit from the bottom of the pot. Cook for 2 to 3 minutes until the wine has almost fully evaporated and the alcohol smell has cooked off.
- 5 Add the stock and simmer: Pour in the beef stock. Add the Worcestershire sauce, thyme sprigs, bay leaf and black pepper. Stir to combine. Bring to a gentle simmer. Cook uncovered for 15 minutes. Taste the broth and adjust seasoning with salt and pepper. Remove and discard the thyme sprigs and bay leaf.
- 6 Toast the baguette: While the broth simmers, slice the baguette into thick rounds. Toast under the broiler or in a toaster oven until completely dry, golden and very crispy on both sides. The bread must be very dry. Soft bread dissolves into the soup within seconds and creates an unpleasant mushy texture.
- 7 Assemble and broil: Preheat the broiler to high. Place the oven safe soup bowls on a baking tray. Ladle the hot soup into each bowl. Place 2 toasted baguette rounds on top of the soup in each bowl. Pile a generous heap of freshly grated Gruyere over the bread. Place under the broiler for 3 to 5 minutes until the cheese is melted, bubbling and deeply golden in patches. Serve immediately.
Nutrition (Per Serving — 1 of 4 bowls with baguette and cheese)
* Nutritional values are estimates per serving including two baguette rounds and Gruyere cheese topping. Using less cheese reduces fat and calories. Vegetarian stock reduces sodium slightly.
Notes
- The caramelization step cannot be rushed. If you increase the heat to speed things up, the onions will burn on the outside before the sugars have time to develop properly. Low and slow is the only correct approach for this French Onion Soup Recipe.
- You need oven safe bowls for this recipe. Standard soup bowls will crack or shatter under the broiler. Use ceramic ramekins, French onion soup crocks or any oven safe bowl rated for broiler use.
- Toast the baguette slices until they are very dry and completely hard. If the bread has any softness remaining it will dissolve into the soup and create a soggy, unpleasant texture rather than a firm, satisfying topping.
- The soup base stores in the refrigerator for up to 4 days and freezes for up to 3 months. Always add the bread and cheese fresh just before serving. Never store assembled bowls as the bread becomes completely unusable.
- This French Onion Soup Recipe serves 4 generously. To serve 6, increase the stock to 1.4 litres and add a couple more onions. The caramelizing time remains the same.
Tips for the Best French Onion Soup Recipe Results
- Use a wide, heavy bottomed pot for caramelizing the onions. A wide base means more surface area for moisture to evaporate. Furthermore, the onions caramelize more efficiently and evenly than in a narrow, tall pot.
- Stir the onions every 3 to 4 minutes during caramelization — not constantly. Constant stirring prevents the sugars from developing the caramelized bits on the bottom of the pan. Those sticky bits are where all the deepest flavor lives.
- If the onions start to stick, add a tablespoon of water and scrape up the fond from the bottom. This is called deglazing mid cook. Moreover, it incorporates all that concentrated flavor back into the onions rather than burning it.
- Be generous with the Gruyere. A thin coating of cheese melts too quickly and does not develop the deeply golden, slightly charred spots that make French Onion Soup Recipe visually stunning. Pile it on thickly and unevenly.
- Watch the bowls carefully under the broiler. The cheese goes from perfectly golden to burnt very quickly. Furthermore, different ovens have different broiler intensities. Check every 60 seconds after the first 3 minutes.
- Let the bowls rest for 2 minutes after removing from the broiler. The soup and bowls are extremely hot. On the other hand, the brief rest allows the temperature to drop slightly to a safe eating level without losing any of the wonderful heat.