Classic French Onion Soup is absolutely loaded with rich caramelized onions, melted cheese on top of baguette slices, and a deep, savory broth. Made with fresh, real ingredients, it's 1,000x better than anything from a store and can be made ahead and reheated for a light lunch of fantastic dinner side.
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French onion soup is a bistro favorite and one that I love to order when we go out to eat. Sometimes I'll make it my lunch with a salad on the side, but other times it's a great appetizer or side dish to a meal.
I used to get it when we had a Mimi's Cafe nearby, but that location closed so I learned to make it at home myself. Honestly, I think my version is even better.
What is French Onion Soup?
French Onion Soup is a classic French dish made with caramelized onions, a rich beefy broth, and topped with golden bubbly melted gruyere cheese and toasted bread. The onions are typically slow-cooked until they become sweet and caramelized, adding rich flavor to the broth. The soup is often served in individual oven-safe bowls, topped with a slice of baguette or French bread and melted Gruyère or Swiss cheese.
This soup is traditionally served as an appetizer or a starter rather than as a main dish. It's a rich and flavorful soup that is often enjoyed before the main course in a meal. The combination of caramelized onions, beef broth, melted cheese, and toasted bread makes it a hearty and satisfying appetizer. However, some people may choose to have a larger portion and pair it with a salad or other side dishes, turning it into a more substantial meal.
French Onion Soup Ingredients
- Onions - We prefer sweet onions for French onion soup, but yellow onions also work well. You could even make this recipe with red onions, shallots, or even leeks, although the flavor will be slightly different for each.
- Salted Butter - For cooking the onions.
- Sugar - I like to add just a small amount of granulated sugar to help bring out the natural sugars and sweetness of the onions while they caramelize.
- Salt & Pepper
- Garlic - Use fresh minced garlic for the best flavor.
- Flour - A small amount of flour helps thicken the soup every so slightly so it has some body to it.
- White Wine - This is an optional ingredient but it's traditionally used to add flavor and body to the soup and the alcohol boils off completely, keeping this a family friendly soup recipe. You can absolutely omit this ingredient if you want to make French onion soup without wine.
- Beef Broth - Use a high quality beef broth for the best flavor. You could also use beef stock in place of broth for a meatier flavor, but we find that it can overpower the onion taste of the soup.
- Worcestershire Sauce - Adds depth to the flavor of the soup. This ingredient isn't traditional, but it adds umami elements to the soup base that we love and we definitely recommend it if you are omitting the white wine.
- Bay Leaves & Fresh Thyme - This isn't an overly herby soup but the bay leaves and fresh thyme leaves are wonderful. You can use dried thyme instead, if that's what you have on hand.
- Baguette - Everybody's favorite part about french onion soup, right? Use a stale baguette that is 1-2 days old for best results.
- Cheese - Gruyere cheese is the most traditional approach, but I like adding a little freshly grated parmesan or parmigiano reggiano.
How to Make French Onion Soup
- Prep. Add butter to a large pot or dutch oven over medium heat. Once the butter has melted, add the sliced onions, sugar, salt, and pepper. Stir well to coat the onions in the melted butter and evenly distribute the other ingredients. The pot will look quite full, but don't let that worry you since the onions will cook down a lot.
- Caramelize the onions. Cook the onions, stirring occasionally, until softened and starting to turn a deep brown, anywhere from 45-60 minutes. They will look very softened and release a lot of liquid by the time they have been cooking for 20-30 minutes, but keep going and add a splash of broth or water if you need to if the pan starts drying out before the onions are caramelized.
PRO TIP: The amount of time it takes to really caramelize the onions can depend on the size and type of your pot and the heat used, but it is best to take your time and use a lower heat so you don't burn the onions. If they seem to be burning, reduce the heat slightly, be sure to stir them well, and add a splash of water or beef broth. The onions should be caramelized to a deep, rich brown color.
- Sprinkle with flour. Once the onions are fully caramelized, sprinkle the flour over them onions and stir well until the flour has been absorbed, about 30-60 seconds.
- Deglaze the pot. Add the ½ cup of white wine (or just ½ cup of the beef broth, if you want to make this french onion soup recipe without wine) and increase the heat to high heat. Use a wooden spoon to deglaze the bottom of the pot by scraping up any browned bits (called fond, which gives loads of flavor) until the onions are almost jam-like in consistency. Continue to cook until the wine has completely cooked down and evaporated to the point that there is no more liquid in the pot.
- Combine ingredients. Add beef stock, garlic, bay leaves, thyme, salt, and pepper. Stir well, then bring to a boil.
- Simmer. Once boiling, cover the pot with a lid. Reduce the heat to low and simmer for 20 minutes.
- Prep the baguette slices. While the onions cook, preheat oven to 400°F. Arrange sliced baguette pieces on a baking sheet. Once the oven is hot, toast the bread for 8-10 minutes until lightly golden and crisp.
- Portion. Set 6 oven-safe bowls on a baking sheet. Ladle the hot soup into the bowls, evenly distributing it.
PRO TIP: If you don't have oven-safe soup bowls, you can just toast the bread and cheese on a baking sheet and then add them to the soup before serving instead.
- Top. Cover each bowl of soup with slices of baguette, making sure they don't overlap. Sprinkle the shredded gruyere cheese on top of the bread.
- Broil. Turn on the oven broiler and carefully transfer the baking sheet with the soup bowls to the oven under the broiler. Broil just until the cheese is melted and starts to bubble and toast. Serve immediately.
Recipe FAQ's
French onion soup is fantastic with a crisp garden salad, but it's also delicious with a protein like grilled chicken or steak. It also makes a nice side with fish dishes like pan-fried trout.
Go slow. Take your time and don't rush the process. Some folks are intimidated by making caramelized onions thinking that they will burn them, but it's actually very simple if you keep the heat low and give them time to soften and draw out the natural sugars in the onions. Follow the tips in the recipe card and you will be fine!
Beef stock is made by simmering beef bones, along with vegetables and herbs. It tends to have a deeper, more intense flavor. Beef broth is made by simmering meat (such as beef chunks or ground beef) along with vegetables and herbs. It generally contains a higher proportion of meat compared to bones and has a lighter flavor compared to stock. We prefer using beef broth in our french onion soup recipe because it provides a flavorful base without being too heavy or overpowering the sweet, caramelized onions.
Choose a cheese with good melting properties. Gruyère and Swiss cheese are popular choices for French Onion Soup due to their melting qualities and complementary flavors, but provolone, mozzarella cheese, or even monterey jack can all work well.
Substitute beef broth with vegetable broth or mushroom broth for a vegetarian version of French Onion Soup. Vegetable broth provides a lighter base while allowing the caramelized onions to shine. If you're open to using a different meat broth, chicken broth can be used as an alternative. While it won't be traditional French Onion Soup, it can still be delicious. You could also do a combination of any of the broths mentioned above along with beef broth if you don't have quite enough of one or the other on hand or have some that you want to use up.
When adding the cheese and bread to the soup, be generous with the amount. Cover the entire surface of the soup with cheese and ensure that it extends to the edges of the bowl. If you're using cheese slices instead of grated cheese, overlap the slices slightly. This creates a more cohesive layer and helps prevent the cheese from sinking into the soup. Place the bread slices on top of the soup in a way that they are floating and not submerged. This helps the bread absorb the broth without dragging the cheese down. After adding the cheese and bread, broil the soup in the oven to help create a golden and bubbly crust on the cheese, preventing it from sinking.
Yes, this soup freezes well. We recommend freezing the soup in individual portions for easier reheating. Freeze the soup without the bread or cheese for up to 3 months, then thaw overnight in the fridge and reheat on the stovetop before adding to bowls and topping with baguette slices and cheese and toasting in the oven.
Yes, absolutely. Simply replace the wine in the recipe with additional beef broth or water. If making this recipe without wine, I also recommend adding 1 ½ Tablespoons balsamic vinegar for more body and flavor.
French Onion Soup Tips
- Serve right away. Serve the French Onion Soup immediately after broiling to enjoy the gooey, melted cheese at its best. The longer the soup sits, the more likely the cheese may start to sink.
- Make-Ahead. You can make the soup broth ahead of time and wait to top them with the bread and cheese when ready to enjoy. The soup broth can be made up to 3 days ahead and refrigerated, then reheated before adding the toasted baguette and cheese.
More Soup Recipes
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- Zuppa Toscana Soup
- Wisconsin Cauliflower Soup
- How to Make Italian Wedding Soup
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Classic French Onion Soup Recipe
Ingredients
- 5 Tablespoons salted butter
- 4-5 large sweet onions, thinly sliced (about 3 pounds)
- 1 teaspoon granulated sugar
- ½ teaspoon salt
- ½ teaspoon black pepper
- 3 cloves garlic, minced
- 2 Tablespoons all-purpose flour
- ½ cup dry white wine (optional)
- 8 cups beef broth
- 1 teaspoon Worcestershire sauce
- 2 bay leaves
- 2 sprigs fresh thyme (about 1 Tablespoon fresh thyme leaves or ½ teaspoon dried thyme)
- 1 day-old baguette, sliced into ½-inch thick slices
- 6-8 ounces gruyere cheese, freshly grated
- ½ cup freshly grated Parmigiano Reggiano cheese
Instructions
- Add butter to a large pot or dutch oven over medium heat. Once the butter has melted, add the sliced onions, sugar, salt, and pepper. Stir well to coat the onions in the melted butter and evenly distribute the other ingredients.
- Cook the onions, stirring occasionally, until softened and starting to turn a deep brown, anywhere from 45-60 minutes. The amount of time it takes to really caramelize the onions can depend on the size and type of your pot and the heat used, but it is best to take your time and use a lower heat so you don't burn the onions. If they seem to be burning, reduce the heat slightly, be sure to stir them well, and add a splash of water or beef broth. The onions should be caramelized to a deep, rich brown color.
- While the onions cook, preheat oven to 400°F. Arrange sliced baguette pieces on a baking sheet. Once the oven is hot, toast the bread for 8-10 minutes until lightly golden and crisp.
- Once the onions are fully caramelized, sprinkle the flour over them onions and stir well until the flour has been absorbed, about 30-60 seconds.
- Add the ½ cup of white wine (or just ½ cup of the beef broth, if you want to make this french onion soup recipe without wine) and increase the heat to high heat. Use a wooden spoon to deglaze the bottom of the pot by scraping up any browned bits (called fond, which gives loads of flavor) until the onions are almost jam-like in consistency. Continue to cook until the wine has completely cooked down and evaporated to the point that there is no more liquid in the pot.
- Add beef broth garlic, bay leaves, thyme, salt, and pepper. Stir well, then bring to a boil.
- Once boiling, cover the pot with a lid. Reduce the heat to low and simmer for 20 minutes.
- Set 6 oven-safe bowls on a baking sheet. Ladle the hot soup into the bowls, evenly distributing it, then cover each bowl of soup with slices of baguette, making sure they don't overlap. Sprinkle a generous amount of the gruyere and freshly grated Parmigiano Reggiano cheeses on top of the bread slices in each bowl.
- Turn on the oven broiler and carefully transfer the baking sheet with the soup bowls to the oven under the broiler. Broil just until the cheese is melted and starts to bubble and toast. Serve immediately.
Notes
- Onions: Vidalia onions or sweet onions work best, although you can also use yellow onions.
- Cheese: Choose a cheese with good melting properties. Gruyère and Swiss cheese are popular choices for French Onion Soup due to their melting qualities and complementary flavors, but provolone, mozzarella cheese, or even monterey jack can all work well.
- Make-Ahead: The soup broth can be made up to 3 days ahead and refrigerated, then reheated before adding the toasted baguette and cheese.
- Freezing: You can freeze the soup for up to 3 months. Thaw, reheat, then add the sliced baguette and cheese.
- Without wine: If making this recipe without wine, I also recommend adding 1 ½ Tablespoons balsamic vinegar for more body and flavor.
My mouth was watering just reading the recipe but the flavor was even more than I could have thought possible! So delish!
Your recipe looks easy and sounds delicious. But what do you do with the 1/2 cup of grated Parmigiano Reggiano cheese called for at the end of the ingredient list.
Good catch. I like to add it to the gruyere cheese when I toast the bread. I fixed the instructions. I hope you enjoy it, it's a good one!