An intensely savory caramelized onion broth topped off with a thick, toasty hunk of bread, all beneath a lid of golden, bubbly cheese, classic French onion soup is a masterpiece.
French onion soup ingredients—onions (lots of them), beef broth, a bit of white wine, bread, and cheese—are humble.
One secret ingredient transforms them into one of the world’s greatest comfort foods: time.
French onion soup tastes like sweet caramelized onions, with intense savory notes from beef broth, wine, and brandy.
The consistency is brothy at first, but as the bread soaks up some of the liquid, it thickens. It’s heavenly.
About French Onion Soup
French onion soup is actually French, and it remains popular in France to this day.
If you’d like to order French onion soup in France, it’s soupe à l’oignon.
While stories as to who first made it abound (was it Louis XV at his hunting lodge? Duke of Lorraine, father of the Queen of France?), its rise to popularity is rooted in practicality—onions were in expensive, making the soup economical.
(Another fun story: apparently the strong scent of the Gruyere cheese on top masked the smell of alcohol from the night before, and it was a popular hangover food.)
Since we can’t go back in time (or hop a flight to Paris!) anytime we’re craving it, I set out to create an authentic French onion soup recipe that lived up the French onion soups I’ve tried in France.
This is it! Let’s make the world’s best French onion soup.
How to Make the Best French Onion Soup
French onion soup broth is made of caramelized onions, beef broth, wine, and one very important addition…
The secret ingredient in French onion soup is time.
- To deepen the flavor of French onion soup, the onions need 45 minutes or longer to caramelize.
- From there, you add a few flavor enhancers—wine, brandy, and beef stock—but without that caramelized onion base, you won’t have the bewitchingly complex French onion soup of your dreams.
Start the onions sautéing in the background, then carry on with other tasks in the kitchen and give the onions a stir every few minutes.
Looking for a quicker version? Check out my Instant Pot French Onion Soup.
The Signature Topping
While the onion broth cannot be overlooked since it is the soup’s foundation, it’s not what most of us think of when we picture a bowl of French onion soup.
It’s that cheesy, toasted bread.
- When the toasted bread is placed on top of the soup, its bottom half absorbs the rich broth and becomes soft.
- The top stays crispy.
- The melty cheese oozes all over everything.
Digging your spoon through those baguette slices and into the soup below is nothing short of a pleasure.
When you eat them all together, that’s the magic of French onion soup!
- Yellow Onions. Frequently a member of the supporting cast, onions get their moment at center stage in this recipe. Their inherent sweetness is celebrated through the caramelization process. They become ultra tender and add momentous depth of flavor to the broth.
- Butter. This is French and butter is a must-have. It helps add rich flavor to the onions as they’re caramelizing.
- Wine. While you can make French onion soup without wine (simply use additional beef stock to deglaze the pot and a dash of Worcestershire sauce for complexity), I love the touch of acid wine adds to cut through the richness, and it just feels so French. White wine or dry vermouth (a fortified wine) are classic. Red wine can also be used.
- Beef Stock. Traditional French recipes (like Julia Child’s French onion soup) call for homemade beef stock or broth, but I don’t think it’s necessary to have delicious French onion soup. I have great results with good-quality, store-bought broth.
- Bay Leaf. Adds a subtle savoriness.
- Brandy. Pulls all the flavors together and adds a hint of sweetness.
- Cheese Toast Slices. A slice of French bread or baguette topped with olive oil and Gruyère cheese is a major selling point for this delicious soup.
- Chives. A tasty way to garnish your soup and add some color. Fresh thyme sprigs are also lovely.
- Halve, peel, and cut the onions.
- Melt the butter in a large pot, then add the onions.
- Cook and stir until softened.
- Add part of the salt, then reduce the heat to medium low. Cook and stir until caramelized—this will take 45 minutes or longer. WORTH IT.
- Stir in the wine, scraping up any stuck-on, browned bits from the pan.
- Add the stock, bay leaf, pepper, and remaining salt. Bring the soup to a boil, then let simmer for 30 minutes. Add the brandy. Discard the bay leaf.
- Brush the bread slices with olive oil and toast in the oven at 450 degrees F for 5 to 7 minutes.
- Flip the bread slices over, top with cheese, and bake for another 2 to 3 minutes. Serve in soup bowls with a slice of bread and chives. ENJOY!
- To Store. Refrigerate soup in an airtight storage container for up to 3 days. Store bread separately in an airtight storage container at room temperature.
- To Reheat. Rewarm leftovers in a pot on the stovetop over medium-low heat or in the microwave. If desired, toast leftover bread on a baking sheet in the oven at 350 degrees.
- To Freeze. Freeze soup in an airtight freezer-safe storage container for up to 3 months. Let thaw overnight in the refrigerator before reheating.
Meal Prep Tip
Halve, peel, and cut the onions and grate the cheese up to 1 day in advance. Refrigerate them in separate airtight storage containers until you’re ready to finish the recipe.
Give your leftovers new life by turning them into French onion pasta. Ladle the onions and broth over a bed of cooked whole wheat pasta noodles. Top the pasta with additional cheese or serve with the cheesy toast.
What to Serve with French Onion Soup
This French onion soup is definitely hearty enough to enjoy on its own as a main meal, but here are a few ideas of what would pair well with it:
Recommended Tools to Make this Recipe
- Dutch Oven. Perfect for making soups and stews.
- Cheese Grater. Grating your own cheese is worth the extra step.
- Wooden Spoon. Great for stirring and scraping the bottom of the pot.
The Best Dutch Oven
Classic, versatile, and ready to cook beside you for a lifetime, this Dutch oven is a worthy investment. It comes in a variety of colors.
French onion soup is special.
Yes, it takes time, but once you sink your spoon into that cheesy bread and scoop the savory onion broth below, you’ll know it’s undoubtedly time well spent.
Frequently Asked Questions
Yellow onions are the classic choice for authentic French onion soup and will give great results, but for an even more complex, nuanced flavor, use a mix. Try any blend of sweet onions like Vidalia onions, red onions, white onions, or even shallots.
Gruyere or comté are traditional for French onion soup, though you can use any cheese with a similar nutty flavor that melts well. Swiss cheese or Emmental are the close swaps. Gouda, fontina, or provolone would also work nicely. Mozzarella, while melty, is a little bland for French onion soup, so if you do use it, add some Parmesan cheese to give it a little oomph.
French onion soup is always made with beef stock. Other onion soups can be made with chicken, vegetable, or beef stock. Additionally, French onion soup typically contains wine or sherry, which isn’t typical or necessary in other onion soups. Last, some onion soup recipes are made with cream which is never the case with a classic French onion soup.
If you’d prefer to broil your bread directly on top of your soup instead of on a separate baking sheet, you can do so. Ladle soup into serving-sized, broiler-safe dishes. Top each dish with a slice of the bread. Add grated cheese to the top of each slice. Broil for 1 to 2 minutes, just until the cheese is melted and lightly browned.
While it’s not traditional, you could certainly try adding chicken, beef, or even chickpeas to French onion soup if you want some extra protein. I have not personally tried it with this recipe, so it would be an experiment. One easy option would be to stir in some cooked shredded chicken right before serving. Do note however that traditional French onion soup is made without meat (and is plenty filling!).
- 3 pounds yellow onions or a mix of yellow and red (about 6 large)
- 4 tablespoons unsalted butter
- 1 1/2 teaspoons kosher salt divided
- 1/2 cup dry white wine or dry vermouth see notes if omitting
- 8 cups unsalted beef stock*
- 1 bay leaf
- 1/2 teaspoon ground black pepper
- 2 tablespoons brandy or 1 tablespoon dry sherry
- 6 (1-inch thick) slices French bread or baguette
- 1 1/2 tablespoons extra-virgin olive oil
- 1 1 /2 cups grated Gruyere cheese about 6 ounces
- Chopped fresh chives optional
Halve the yellow onions through the stem ends and remove the peels. Cut lengthwise into 1/4-inch thick slices. You should have about 10 cups of onions total.
In a large Dutch oven or similar large, deep pot, melt the butter over medium-high heat. Once the butter melts, add the onions.
Cook, stirring the onions every minute or so, until they soften, about 8 minutes.
Stir in 1/2 teaspoon of the salt. Reduce the heat to medium low to caramelize the onions.
Continue cooking, stirring periodically, until the onions are a rich, even golden brown color. Adjust the heat as needed so the onions become meltingly tender and reduce in volume significantly but do not burn (depending upon how your pot conducts heat, you may need to reduce the heat to low for a while); if at any point the juices on the bottom of the pot start to stick, add 1 to 2 tablespoons of water and use a wooden spoon to scrape the bottom of the pot as needed. The length of time onions take to caramelize will vary based upon your pot, stove, and onions (enamel takes longer than cast iron or stainless steel). Plan on about 45 to 60 minutes.
Deglaze the pot: Increase the heat to medium high. Pour in the wine and use a wooden spoon to scrape up any stuck-on bits. Let simmer 1 minute.
Add the stock, bay leaf, pepper, and remaining 1 teaspoon salt. Increase the heat to bring to a boil, then reduce the heat to maintain a gentle but steady simmer. Continue simmering uncovered for 30 minutes more. Stir in the brandy. Taste and adjust seasoning as desired (depending upon your stock, you may want a bit more salt). Fish out and discard the bay leaf.
Meanwhile, make the toasted bread: Place a rack in the upper third of your oven and preheat to 450 degrees F. Line a baking sheet with parchment paper. Brush both sides of the bread slices lightly with olive oil. Arrange on the prepared baking sheet and toast on the upper rack until lightly browned, 5 to 7 minutes. Set aside.
Just before serving, flip each slice of bread over and sprinkle with 1/4 cup of the cheese. Return to the oven and toast until the cheese is melted and golden, about 2 to 3 minutes. Ladle the soup into bowls, top with a bread slice, and serve with a sprinkle of chopped chives.
- *If using regular or even reduced sodium beef stock instead of unsalted, reduce the salt added in step 5 to 1/2 teaspoon; salt at the end to taste.
- If you prefer not to cook with alcohol, simply leave it out! You can use part of the beef stock to deglaze the onions.
- TO COOK IN INDIVIDUAL CASSEROLE DISHES: Instead of toasting the bread separately, ladle the cooked soup into individual broiler-safe dishes. Lay a bread slice on top (no need to brush with oil) and sprinkle with cheese. Broil 1 to 2 minutes, until the cheese is melted and browned.
- TO STORE: Refrigerate soup in an airtight storage container for up to 3 days. Store bread separately in an airtight storage container at room temperature.
- TO REHEAT: Rewarm leftovers in a pot on the stovetop over medium-low heat or in the microwave. If desired, toast leftover bread on a baking sheet in the oven at 350 degrees.
- TO FREEZE: Freeze soup in an airtight freezer-safe storage container for up to 3 months. Let thaw overnight in the refrigerator before reheating.
Serving: 1(of 6)Calories: 470kcalCarbohydrates: 31gProtein: 23gFat: 26gSaturated Fat: 14gPolyunsaturated Fat: 1gMonounsaturated Fat: 9gTrans Fat: 0.3gCholesterol: 68mgPotassium: 978mgFiber: 4gSugar: 12gVitamin A: 657IUVitamin C: 17mgCalcium: 527mgIron: 2mg
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