French onion soup often a staple in restaurants, actually originated as a humble peasant soup made with just onions, stale bread, and water. Today’s versions might be a bit fancier, but this soup is still tasty and simple to make at home. The key is patience.
The onions need to be cooked low and slow so that they sweeten and turn a rich brown caramel color without burning. In addition to giving the onions the proper time and attention, I add a bit of sugar to make the sweetness of the onions.
I also stir in a bit of flour to add ingredients to the broth—two tricks I picked up working in a French restaurant that made the best French onion soup ever. Finally, to add even more flavor, I top the croutons with two types of cheese.
The Secret Ingredient Is Time
The second most important thing is to properly caramelize the onions. Caramelizing the amount of onions needed in this recipe will take at least 40 minutes. Caramelizing is a chemical process that occurs when the sugars in the onions reach a certain temperature.
This only happens after a long cooking time (the addition of a little extra sugar will help). The more caramelized, the deeper the color of the onions and the more flavor you’ll get from them.
NOTE: Much of the taste of this soup depends on the stock that you are using, and stock varies in its taste. Depending on your stock, you may need to bump up the flavor with some beef bouillon (we recommend the Better than Bouillon brand).
Ingredients of French onion soup
- 6 large red or yellow onions (about 3 pounds)
- 4 tablespoons extra virgin olive oil
- 2 tablespoons butter
- 1 teaspoon sugar
- Kosher salt
- 2 cloves garlic, minced
- 8 cups beef stock, chicken stock, or a combination of the two
- 1/2 cup dry vermouth or dry white wine
- 2 bay leaves
- 1 tablespoon fresh thyme leaves, a few sprigs of fresh thyme, OR 1/2 teaspoon dried thyme
- 1/2 teaspoon freshly ground black pepper
- 2 tablespoons brandy (optional)
- 8 slices (1 inch thick) French bread or baguette
- 1 1/2 cups grated Gruyere cheese
- Sprinkling grated Parmesan cheese
How To Make the Best French Onion Soup
There are two essential ingredients of a good French onion soup.
The first is the stock. Your soup will only be as good as the stock you are using. This soup traditionally is made with beef stock, though sometimes a good beef stock can be hard to come by and expensive to make.
If you use boxed stock, taste it first! If you don’t like the taste, don’t use it. (If you cook a lot of beef or beef roasts, save the scraps and freeze them to make a stock later.)
Step-by-step Guide
1. Peel and slice the onions:
Peel and thinly slice the onions from root to stem. There should be about 10 cups of sliced onions in total.
2. Begin caramelizing the onions with olive oil and butter:
In a 5 to 6-quart thick-bottomed pot, heat 3 tablespoons of olive oil on medium heat. Add the onions and toss to coat with the olive oil.
Cook the onions, stirring often, until they have softened, about 15 to 20 minutes.
Increase the heat to medium-high. Add the remaining tablespoon of olive oil and the butter and cook, stirring often, until the onions start to brown, about 20 to 40 minutes. The amount of time will vary depending on your pot, stove, and onions.
3. Sprinkle with the sugar, finish caramelizing, and add garlic:
Sprinkle with sugar (to help with the caramelization) and 1 teaspoon of salt. Continue to cook until the onions are well browned, about 10 to 15 more minutes.
Add the minced garlic and cook for a minute more.
4. Deglaze the pot with vermouth or wine:
Add the wine or vermouth to the pot and scrape up the browned bits on the bottom and sides of the pot, deglazing the pot as you go.
5. Add the stock, bay leaves, and thyme:
Add the stock, bay leaves, and thyme. Bring to a simmer, cover the pot, and lower the heat to maintain a low simmer. Cook for about 30 minutes.
6. Season and add the brandy:
Season to taste with more salt and add freshly ground black pepper. Discard the bay leaves. Add brandy if using.
7. Toast the French bread slices:
While the soup is simmering, line a sheet pan with parchment paper or foil and preheat the oven to 450°F with a rack in the upper third of the oven.
Brush both sides of the French bread or baguette slices lightly with olive oil (you’ll end up using about a tablespoon and a half of olive oil for this).
Put in the oven and toast until lightly browned, about 5 to 7 minutes. Remove from oven.
French onion soup to Serve:
To serve, ladle soup into a bowl and transfer one cheesy toast onto the top of each bowl of soup.
Alternatively, you can use individual oven-proof bowls or one large casserole dish. Ladle the soup into the bowls or casserole dish. Cover with the toast and sprinkle with cheese. Put into the broiler for 10 minutes at 350° F, or until the cheese bubbles and is slightly browned.
Alternatives To Wine
The recipe calls for dry vermouth or white wine as well as optional brandy. If you prefer not to use any alcohol, many readers who made the recipe mentioned in the comments that they omit it altogether and it’s still delicious.
Others mentioned adding some Worcestershire sauce at the end to give it an additional depth of flavor. If you omit the alcohol, you may want to add a tablespoon or so of Worcestershire, but it’s not necessary.
If you do choose to omit the alcohol, use a half cup of the beef broth to deglaze the pan as instructed in Step 2 before adding the remaining stock in Step 3.
The Best Cheese To Use for French Onion Soup
Gruyere and Parmesan are the classics for French onion soup. However, if you don’t have them, try these alternatives.
- Gouda
- Swiss
- Fontina
- Mozzarella
How To Store and Reheat French onion soup
Store the soup—without the croutons—in an airtight container in the refrigerator for 3 to 4 days. To reheat, bring to a boil on the stovetop. The croutons are best when made fresh.
How To Freeze French Onion Soup
This soup—without the croutons—freezes well. Freeze the cooled soup for up to 3 months. Defrost in the refrigerator and reheat by boiling on the stovetop. Make the croutons fresh.
Did you enjoy this recipe? Let us know with a rating and review!
Recipe!
French Onion Soup
Equipment
- Dutch oven
- Mixing bowls
- pot
- cups
Ingredients
- 6 pound large red or yellow onions (about 3 pounds)
- 4 tbsp extra virgin olive oil
- 2 tbsp butter
- 1 tbsp sugar
- kosher salt
- 2 cloves garlic, minced
- 8 cup beef stock, chicken or a combination of the two
- 1/2 cup dry vermouth or dry white wine
- 2 bay leaves
- 1 tbsp tablespoon fresh thyme leaves, a few sprigs of fresh thyme, OR 1/2 teaspoon dried thyme
- 1/2 tbsp teaspoon freshly ground black pepper
- 8 slices (1 inch thick) French bread or baguette
- 1 1/2 cup grated Gruyere cheese
- Sprinkling grated Parmesan cheese
Instructions
- Melt butter in a heavy based casserole pot over medium heat. When it starts to foam, add onions and stir to coat in butter.
- 30 min on medium low: Turn heat down to medium low. Cook for 30 minutes stirring every few minutes, until the onions have softened and are semi transparent.
- Salt, 20 min on medium-high: Turn the heat up to medium or medium-high. Add salt, and cook for a further 20 – 30 minutes, stirring more regularly, until onions are deep golden and sweet.
“This French Onion Soup recipe is absolutely divine! The caramelized onions and rich broth make for a comforting and flavorful dish. Perfect for a cozy evening at home!”