Name: Classic French Onion Soup Recipe
Prep time: 1 h
Cook time: 5 min
Total time: 1 h 5 min
Yield: 8
Cuisine: French
Ingredients: 1 tbsp (15 ml) olive oil; 1 tbsp (15 g) of butter; 8 medium yellow onions, sliced thinly into half moons; 1 tsp (5 ml) salt; 1 tsp (5 ml) sugar; ¼ cup (60 ml) dry sherry or Cognac; 10 cups (2,500 ml) beef stock; 4 sprigs Thyme (tied with butcher string) + 1 tbsp for garnish; 2 Bay leaves; 1 garlic clove minced; 1 tsp (5 ml) salt; freshly cracked pepper; 1 day old French baguette (sourdough works well) cut into ½ inch slices; 3 cups (300 g) Gruyere cheese

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This Easy French Onion Soup Recipe is one of those classic French recipes that’s absolutely worth mastering. Rich, cozy, and topped with bubbly, golden brown Gruyère cheese, it’s the kind of comforting soup that instantly elevates any meal.

Most people only experience French onion soup at restaurants, which makes a homemade version feel extra special. It’s hearty, elegant, and deeply flavorful, perfect for entertaining or warming up a chilly fall or winter night. Once you’ve made it yourself, it might become your favorite cold-weather comfort food.

What’s the Secret to Great French Onion Soup?

French Onion Soup may seem fancy, but at its heart, it’s a simple, rustic dish built on basic techniques.
The key is the slow caramelization of yellow onions, which transforms them into something deeply sweet and flavorful.
From there, use a flavorful beef broth, a splash of dry sherry (or balsamic vinegar if you prefer), and a topping of crusty bread and Gruyère cheese for a soup that feels indulgent without being fussy.
For more cozy, comforting soup recipes with that same rustic elegance, try my Leek and Potato Soup (No Cream) and this Roasted Cauliflower Soup.

Why You’ll Love This Recipe:

It’s the ultimate comfort food, and it’s great for entertaining, since most of the work can be done ahead of time.
Make the soup base up to 2 days before. Cool and refrigerate.
Then, when it’s time to serve, reheat the soup until warmed through and hot.
Ladle the soup into bowls, add the bread and Gruyère cheese, and broil for a great finishing touch!
It’s an elegant dish with rustic charm, suitable for a cozy family dinner or a fall or winter dinner party.

Ingredients:

Olive Oil: Helps the onions cook evenly and prevents the butter from burning; a mild-flavored oil is best here.
Butter: Adds richness and helps the onions caramelize slowly for deeper flavor; use unsalted to control the saltiness.
Yellow Onions: The star of this onion soup recipe; they become sweet and golden when slowly caramelized. Avoid white onions, which can be too sharp.
Salt: Enhances the natural sweetness of the onions and balances the richness of the broth and cheese.
Sugar: Speeds up the caramelization and brings out the onions’ natural sweetness without making the soup sugary.
Dry Sherry: Adds complexity and depth to the soup. If you prefer to skip alcohol, I recommend substituting with 1 teaspoon of balsamic vinegar.
Beef Stock: A rich, flavorful base is essential for classic French onion soup. Homemade is great, but store-bought works too – just choose low-sodium so you can season to taste.
Fresh Thyme: Infuses the broth with subtle herbal notes. Tie it with butcher’s string to remove it easily before serving.
Bay Leaves: Add background flavor and aroma to the broth; just don’t forget to remove them before serving.
Garlic: Just a touch, minced finely, gives the broth extra depth without overpowering the onions.
Freshly Cracked Pepper: Adds a little kick and rounds out the soup’s flavor; adjust to taste.
Day-Old French Baguette: Slightly stale bread holds its shape better once broiled. I recommend sourdough for a sturdier texture and tangy flavor. Slice it the day before and place it into a Ziploc bag; otherwise, if you wait to slice it the next day, it will be too hard to slice.
Gruyère Cheese: The classic choice for that golden, bubbly top. It melts beautifully and adds a slightly nutty flavor.

Sliced onions, herbs, cheese and bread laid out on a cutting board. — The ingredients for French Onion Soup are pretty basic, but the taste is sublime!

Step#1: Prep the Onions

For this recipe, you’ll use eight yellow onions. This may sound like a crazy amount of onions, but they will wilt down once cooked. I also find this makes for a great French Onion soup, lots of caramelized onions! Otherwise, it ends up being too watery.
This step takes some time, but it gives the soup its rich, signature flavor.
In a Dutch oven or large soup pot, heat the olive oil and butter over medium heat.
Add the sliced yellow onions, salt, and sugar.
Cook uncovered, stirring occasionally, until the onions are deeply golden and caramelized.
The onions should be wilted with a deep amber color.

Caramelized onions in a Dutch Oven. — This is what the onions should look like. Wilted down with a deep caramel flavor.

How Long Does it Really Take to Caramelize Onions?

Properly caramelizing onions takes about 20 to 25 minutes over medium heat, with occasional stirring.
You’re looking for a deep golden brown color (more jammy than crispy).
It’s important not to rush the process or crank up the heat, or the onions will burn instead of caramelize.

How Do I Keep the Onions from Burning?

Keep the heat at medium and don’t rush the process.
Stir them now and then, and if they start sticking or browning too fast, just add a splash of water to loosen them up.
You want them golden and jammy, not crispy or dry.

Step #2: Deglaze and Build the Broth

Once the onions are caramelized, it’s time to add depth and complexity to the soup.
Add the dry sherry to the pot, scraping up the browned bits at the bottom of the pan, and stir for 1 minute to allow the alcohol to evaporate.
Stir in the beef stock, garlic, bay leaves, and the thyme bundle.
Cover and simmer over medium heat for 10 minutes to allow the flavors to come together.

Beef broth simmering in a Dutch oven with herbs and onions. — Simmer the onions, herbs, and beef broth for at least 10 minutes to allow the flavors to marry.

Do I Need to Use Sherry?

I do love the flavor dry sherry adds, but if you don’t have any on hand, you can also use Cognac.
If you prefer to skip the alcohol, you can use 1 teaspoon of balsamic vinegar instead.
It gives the onions a very similar depth and balances the richness of the broth.

Step #3: Prepare the Toppings

While the soup simmers, prep your bread and cheese so everything is ready to go under the broiler.
Slice your day-old French baguette or sourdough into ½ inch slices.
Grate the Gruyère cheese and set aside.
Preheat your oven to the broil setting.

Tips on the Bread:

A crusty day-old baguette works best. A sourdough baguette is great, too, if you live in the U.S.
Since the bread, when it’s day old or a dense sourdough, will hold up better to the heat of the soup.
If you use a fresh baguette, the interior crumb will practically disintegrate into the hot soup since it is so soft.
When you buy the baguette, slice it for the soup, transfer it into a slightly opened Ziploc bag, and leave it on your countertop. This will dry out the bread and prevent condensation from forming.
This also avoids the more difficult task of cutting day-old bread that is starting to harden.

What’s the Best Cheese for French Onion Soup?

Gruyère is the classic choice. It melts beautifully and adds a rich, nutty flavor.
For a more affordable option, Trader Joe’s sells a Gruyère/Swiss blend that works well.
If you can’t find Gruyère, Comté, Swiss, or Emmental are all good alternatives, make sure it’s something that melts well.
White cheddar or mozzarella will give you that gooey texture, but the flavor is milder, so I’d recommend adding a little Parmesan on top to boost it.

Step #4: Assemble and Broil

This final step gives the soup its signature finish with crispy bread and melty cheese.
The bread functions like big, gooey croutons and adds so much to this soup.
Ladle the soup into heat-safe, shallow bowls and place them on a rimmed baking sheet.
Top each bowl with two slices of bread and sprinkle about ½ cup of Gruyère cheese on top.
Place under the broiler until the cheese is bubbly and golden brown, keeping a close eye to prevent burning.
Garnish with fresh thyme and serve the bowls on plates to protect your table from the heat.

grated cheese on top of the bread in a French Soup Bowl. — Be generous with the cheese for a gooey finish.

What’s the Best Way to Store and Freeze French Onion Soup?

You can make the soup base ahead of time and store it in the fridge for up to 3-4 days.
If you want to freeze it, just skip the bread and cheese, and portion the soup into airtight containers.
When you’re ready to serve, reheat the soup, top with bread and cheese, and broil until bubbly.

Can I make it ahead for a dinner party?

This is actually one of my favorite soup recipes for entertaining because you can make the whole base a day in advance.
Then right before serving, just reheat it, add your bread and cheese, and finish under the broiler. It couldn’t be easier.

Pro Tips

Don’t skip tying your thyme bundle with butcher’s string. It makes it easy to remove without fishing around in hot broth.
Broil the soup on a foil-lined baking sheet to catch any cheese drips and make cleanup easier.
If your bread is too soft, toast it briefly before adding it to the soup. It’ll hold its shape better under the broiler.

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