French Onion Soup

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This classic French onion soup topped with melted gruyère and parmesan is the epitome of rustic comfort food.

French Onion Soup

Most people think of French onion soup as “restaurant food” but it actually originated as a simple peasant dish made from onions, stale bread, and water. Modern versions of onion soup are more elevated but it’s still easy 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 color without burning.

In addition to giving the onions the proper time and attention, I use a few little tricks I picked up while working in a French restaurant, like adding a bit of sugar to enhance the sweetness of the onions, stirring a bit of flour into the onions to add body to the broth, and topping the croutons with both Gruyère and Parmigiano-Reggiano.

If you don’t have ovenproof crocks for the soup, don’t worry. You can just top your soup with melty cheese toasts or serve them on the side. And if you want to get a head start, go ahead and make the broth and toasts several days ahead of time. When it’s time to eat, simply top the soup with the toasts and cheese and flash the crocks under the broiler.

What you’ll need to make French Onion Soup

ingredients for french onion soupHow To Make French Onion Soup

To begin, in a large Dutch oven or soup pot, melt the butter over medium heat. Add the oil, onions, salt, pepper, and sugar.

caramelizing onions in Dutch oven

Cook, stirring occasionally, until the onions are deep golden brown and caramelized, 45 to 55 minutes.

caramelizing onions in Dutch oven

In the beginning, you will only need to stir the onions only occasionally. As they start to brown midway through cooking, you’ll need to stir them more frequently. Also be sure to scrape the fond (or brown particles) from the bottom of the pan.

caramelizing onions in Dutch ovenAdd the wine and raise the heat to high.

adding wine to Dutch oven

Cook, stirring with a wooden spoon to scrape any fond from the bottom of the pan, until almost all of the liquid has evaporated and the onions are jammy, 8 to 10 minutes.

jammy onions and wine in Dutch ovenAdd the flour.

adding flour to thicken

Cook for about one minute to dissolve the flour.

stirring flour and onions

Add the broth, Worcestershire sauce, thyme, and bay leaves to the pot.

adding broth and herbs to pot

Bring to a boil, reduce the heat to a simmer, and cook, covered, for about 30 minutes. Add the sherry, then taste and adjust seasoning if necessary. If the soup needs a deeper flavor, try a few shakes of Worcestershire sauce. If it’s not quite sweet enough, add 1/4 teaspoon sugar.

finished french onion soup broth

While the soup simmers, preheat the oven to 400°F and set an oven rack in the middle position. Arrange the baguette slices in a single layer on a baking sheet.

toasting bread for topping french onion soup

Bake until the bread is dry, crisp, and golden at edges, about 10 minutes. Set aside.

toasted bread

Adjust an oven rack 6 inches from broiler element and heat broiler. Set individual broiler-safe crocks on a baking sheet and divide the hot soup among the crocks. Be sure the soup is very hot as it won’t warm up much in the oven. Top each crock with 1 or 2 baguette slices (do not overlap slices).

topping crocks with bread

Sprinkle evenly with Gruyère and then Parmigiano Reggiano.

crocks with cheese ready to broil

Slide the crocks into the oven and broil until the cheese is melted and bubbly around edges, 3 to 5 minutes. (Alternatively, if using regular soup bowls: Top each toast slice with some cheese and return to broiler to melt, about 2 minutes more. Divide the soup among bowls and top each serving with two cheese toasts.)

french onion soup crocks out of the oven

Let the French onion soup crocks cool for a few minutes before serving.

french onion soup in serving bowls

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French Onion Soup

This classic French onion soup topped with melted gruyère and parmesan is the epitome of rustic comfort food.

Servings: 4 to 6

Ingredients

  • 4 tablespoons unsalted butter
  • 1 tablespoon vegetable oil
  • 3 pounds Vidalia (or sweet) onions (about 5 medium), halved lengthwise and thinly sliced
  • 3/4 teaspoon salt
  • 1/2 teaspoon freshly ground black pepper
  • 3/4 teaspoon granulated sugar
  • 1 cup dry white wine
  • 2 tablespoons all-purpose flour
  • 6 cups beef broth
  • 1 teaspoon Worcestershire sauce
  • 1/2 teaspoon dried thyme
  • 2 bay leaves
  • 1 small baguette, cut into 1/2-in slices
  • 1 tablespoon dry sherry
  • 8 ounces Gruyère cheese, grated (about 2 heaping cups; look for one imported from Switzerland)
  • 1/2 cup grated Parmigiano Reggiano

Instructions

  1. In a large Dutch oven or soup pot, melt the butter over medium heat. Add the oil, onions, salt, pepper, and sugar. Cook, uncovered, stirring occasionally with a wooden spoon, until onions are deep golden brown and caramelized, 45 to 55 minutes. In the beginning, you will only need to stir the onions only occasionally. As they start to brown midway through cooking, you will need to stir them frequently, scraping the fond (the brown particles) from the bottom of the pan. If the onions are browning too quickly, reduce the heat slightly or add a few tablespoons of water to deglaze the pan and continue cooking.
  2. Add the wine and raise the heat to high. Cook, stirring with a wooden spoon to scrape any fond from the bottom of the pan, until almost all of the liquid has evaporated and the onions are jammy, 8 to 10 minutes.
  3. Add the flour and cook, stirring constantly, for one minute.
  4. Add the broth, Worcestershire sauce, thyme, and bay leaves to the pot. Bring to a boil, reduce the heat to a simmer, and cook, covered, for about 30 minutes.
  5. While the soup simmers, preheat the oven to 400°F and set an oven rack in the middle position. Arrange the baguette slices in a single layer on a baking sheet and bake until the bread is dry, crisp, and golden at edges, about 10 minutes. Set aside.
  6. When the soup is finished, add the sherry; taste and adjust seasoning if necessary. If the soup needs a deeper flavor, try a few shakes of Worcestershire sauce. If it's not quite sweet enough, add 1/4 teaspoon sugar.
  7. Adjust an oven rack 6 inches from broiler element and heat broiler. Set individual broiler-safe crocks on a baking sheet and divide the hot soup among the crocks (be sure the soup is very hot as it won't warm up much in the oven). Top each crock with 1 or 2 baguette slices (do not overlap slices) and sprinkle evenly with Gruyère and then Parmigianno Reggiano. Slide the crocks into the oven and broil until the cheese is melted and bubbly around edges, 3 to 5 minutes. Let the crocks cool for a few minutes before serving. (Alternatively, if using regular soup bowls: Top each toast slice with some cheese and return to broiler to melt, about 2 minutes more. Divide the soup among bowls and top each serving with two cheese toasts.)
  8. Make-Ahead Instructions: The soup can be made and refrigerated up to 3 days ahead (without toasts or cheese), or up to 3 months ahead and frozen. Toasts can be made (without the cheese) and kept sealed at room temperature for up to 3 days.

Nutrition Information

Powered by Edamam

  • Per serving (5 servings)
  • Calories: 642
  • Fat: 31 g
  • Saturated fat: 17 g
  • Carbohydrates: 53 g
  • Sugar: 19 g
  • Fiber: 4 g
  • Protein: 31 g
  • Sodium: 1,697 mg
  • Cholesterol: 82 mg

This website is written and produced for informational purposes only. I am not a certified nutritionist and the nutritional data on this site has not been evaluated or approved by a nutritionist or the Food and Drug Administration. Nutritional information is offered as a courtesy and should not be construed as a guarantee. The data is calculated through an online nutritional calculator, Edamam.com. Although I do my best to provide accurate nutritional information, these figures should be considered estimates only. Varying factors such as product types or brands purchased, natural fluctuations in fresh produce, and the way ingredients are processed change the effective nutritional information in any given recipe. Furthermore, different online calculators provide different results depending on their own nutrition fact sources and algorithms. To obtain the most accurate nutritional information in a given recipe, you should calculate the nutritional information with the actual ingredients used in your recipe, using your preferred nutrition calculator.

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Reviews & Comments

  • I have made this several times, including today, as a rainy day comfort food. I use toasted slices of homemade no knead crusty bread instead of a baguette. This recipe is amazing!

    • — Susan on June 9, 2021
    • Reply
  • I plan to make this soup and don’t have white wine as we are red wine drinkers. I keep a large bottle of Martini and Rossi vermouth on hand for cooking since once opened it will keep so much longer than wine. My question is can I use vermouth in this recipe?
    Many thanks.

    Jan 🇨🇦

    • — Jan on May 11, 2021
    • Reply
    • Sure, Jan, that should work. Hope you enjoy!

      • — Jenn on May 11, 2021
      • Reply
  • The best French Onion Soup I have ever made. Thanks for this excellent recipe. 😷

    • — Joanne Nicholson on February 8, 2021
    • Reply
  • I don’t know why I’ve always been intimidated by the thought of making french onion soup, but I was. No longer! This recipe was not at all difficult, and it was lip-smacking good! I felt like a fancy cook when I served it. Thank you, Jenn, for helping me to be a more confident cook.

    • — Barbara on February 1, 2021
    • Reply
  • This is my first review of a recipe ever…and so a little background. I love to cook and I love French style cooking. (I lived in France one summer with my family and absolutely love the food and the lifestyle…rich foods…full but good fats…fresh in season ingredients…relaxing and enjoying good food with family and friends. We have embodied this ever since. :)) I found Once Upon a Chef and started to follow about 6 months ago. It is the only cooking blog that I choose to follow. The reason…it is the only one out there that I have seen with a classically trained chef (trained in France no less!), and every recipe that I have tried has been amazing. This French Soup recipe is no exception. It is rich and comforting. Perfect for our cold nights! The only thing that I did different is use brown onions (I just prefer them but will try it next time with the sweet onions), gluten free flour, and gluten free French bread on top. I know that real French bread would be much better, but we make do with our gluten sensitivity. Bon Appetit!

    • — Jennifer on January 29, 2021
    • Reply
  • It’s official-this is now our favourite soup! So easy and oh so good. The broth is so flavourful and lower in sodium than what I’ve had in restaurants. I put in only about 2 lbs of onions, personal taste, and use Swiss cheese since it’s something I usually have in the fridge.
    Thanks Jenn for another great recipe.

    • — Ginette on January 29, 2021
    • Reply
  • I have tried many French Onion Soup recipes and this one became my favorite. My family asks for it frequently.

    • — Joan Simmons on January 28, 2021
    • Reply
  • I have always loved French Onion Soup and this one is excellent. It is very easy to make just need to be patient as the onions cook down. I have made it ahead and then assembled when I was ready to serve. I have also frozen it and it tasted just as delicious. It is a wonderful meal for a cold winter night.

    • — Mary Haggerty on January 28, 2021
    • Reply
  • Wonderful recipe, Have made this recipe several times; excellent every time.

    • — Zane Kaminsky on January 28, 2021
    • Reply
  • Best french onion soup I have ever had. I can’t wait to make it again. Was so delicious on a rainy day. Didn’t have Gruyere and didn’t want to leave the house but passed with Havarti.

    • — Christina B on January 28, 2021
    • Reply
  • Delicious! I made this last night for dinner along with the Baby Kale salad after a snowy grey day and it was exactly what my family and I needed. I absolutely love your recipes. I have made many of them, they are easy to follow and always turn out delicious. My husband and daughter have celiac and I never have have an issue substituting GF flour cup for cup with anything including baked items. Thank you!
    -Janet K

    • — Janet Krzemienski on January 28, 2021
    • Reply
  • LOVE this recipe!!! It is so full of flavor. I stopped making my own French Onion Soup because after all the work I found the soups lacked flavor and I was better off buying it at Pa…ra…

    Well with this recipe I’m back to making it myself. I always browned the onions so am guessing the difference comes down to the beef broth (instead of chicken) and the wine. Whatever it is, I love the way this soup comes out and highly recommend it. I make it as the recipe is written. Not sure if it freezes well or not as I never have any leftover to freeze.

    • — Lori Armstrong on January 28, 2021
    • Reply
  • We love this recipe and make it often. We don’t change a thing. I love the process for the read and cheese topping. My husband loves this so much that we buy 10 pound bags of onions to have on hand when he wants it. This soup freezes well also. Give it a try, the effort is worth it, really not laborious and more a labor of love!

    • — Susan on January 28, 2021
    • Reply
  • Outstanding! Truly delicious!

    • — susan kelly on January 28, 2021
    • Reply
  • Jenn,
    I am so excited to try this recipe. Your recipes are always great!
    My question is regarding the dry white wine. In the picture the wine bottle label
    says Vouvray, which I believe is a region in France. Would this be be a Sauvignon Blanc?
    Can you share the winery? I have always heard a Sauvignon Blanc is always best to cook with.
    Is this true? Thank you again for another stellar recipe.
    Dixie

    • — Dixie on January 14, 2021
    • Reply
    • Hi Dixie, so glad you like the recipes! I don’t know what winery that wine was from, that wine but it was a Chenin Blanc. (It was probably just what I had open when I created the recipe.) 🙂 And I wouldn’t worry too much about it as long as you have a dry white wine. Don’t use anything too pricey — when using wine for cooking, something inexpensive (but still good enough to drink) is ideal.

      • — Jenn on January 15, 2021
      • Reply
  • This has to be the best onion soup I’ve ever made. The flavour was layered and deep, without being too salty. It was a huge hit with my family. The only change I made was not using beef stock and replacing it with “veggie” chicken powder. The soup was still amazing – and easily rivals any of the best “soupes à l’onion” I’ve eaten in good French restaurants. Many thanks, Jenn. Your recipes are outstanding.

    • — Montreal Foodie on January 4, 2021
    • Reply
  • A good French Onion Soup depends on the carmelization of the onions to build the broth flavors. This recipe delivers and will now be my go-to for this type of soup. Delicious!

    • — Margaret Yarak on December 30, 2020
    • Reply

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