French Onion Soup

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French Onion Soup is such a classic and SO easy to make! Onions are slowly caramelized until soft and sweet, simmered with beef broth, thyme, sherry, and white wine. It’s topped with a crispy crouton, loads of shredded gruyere cheese and broiled into a crispy, cheesy oblivion. So good!

Soups are our jam, be sure to check out this Award Winning Cheeseburger Soup, this Broccoli Cheese Soup, or this Minestrone Soup. They’re all so amazing and perfect for when it gets chilly!

Top-down view of a bowl of French onion soup, topped with melted gruyere cheese.

French Onion Soup Recipe

I still remember the first time I had French Onion Soup. It was at a fancy steak restaurant when I was about seven years old, and when I saw the next table’s bubbling hot, cheesy soup being delivered to their table, it was love at first sight.

This cheesy, brothy, onion-forward soup may seem hard to make, but it’s actually super easy to prepare. Win! The only thing you need is a little bit of patience both to let the onions caramelize and to keep yourself from inhaling the broth before the cheese goes on to be melted into a gooey oblivion. Let’s get into all of the ingredients you’ll need:

French Onion Soup Ingredients

This classic dish is pure comfort in a bowl, with rich, savory broth simmered with caramelized onions for an unforgettable flavor. Top it off with melted Gruyère and a toasted baguette for the ultimate experience. Let’s dive into the simple ingredients that make the magic happen!

  • Unsalted Butter: Creates a smooth base for sautéing the onions.
  • Onions: Lots and lots of onions. When you let onions cook look and slow, they downsize tremendously. I used about 6 1/2 cups of sliced onions, which equals about 3 large onions. Slice them thin.
  • Salt: Enhances the delicious natural flavor of the onions.
  • All-Purpose Flour: I like to add just a few tablespoons of flour to my French onion soup to thicken it up just a touch.
  • Sherry and Dry White Wine: Deglazes the pan after caramelizing the onions. They also add acidity and complexity to the soup’s flavor. I recommend using sauvignon blanc or pinot Grigio for the white wine.
  • Beef Broth: Use a good-quality beef broth or stock. I also like to use low-sodium, so I can control the amount of salt that goes into the dish.
  • Thyme: Fresh thyme if you’ve got it. About five sprigs.
  • Baguette Slices: Toast nicely and absorbs the soup’s broth.
  • Gruyere Cheese: This is arguably the best part of French onion soup. Gruyere cheese is nutty, salty, and melts PERFECTLY. I would not substitute anything for this. It can be a little bit pricey, but the other ingredients are pretty cheap so it makes up for it.

Do I Have to Use Gruyere?

I would say yes. However, if you can’t find gruyere cheese, you can get away with using emmental or a good swiss cheese. And make sure it’s not pre-shredded. The way you get that gooey interior and crispy exterior is with freshly shredded cheese.

How to Make It

Once you’ve got your ingredients ready, here’s how to make that delicious, ooey-gooey bowl of French onion soup. Once you know how to make it from scratch, you’ll want it all the time!

  1. Melt Butter: Heat a large heavy-bottomed pot over medium heat. Add the butter and let it melt. Add the onions and salt and stir.
  2. Sauté Onions: Let the onions sauté for 5-10 minutes, until they begin to turn translucent. Reduce the heat to medium-low and continue to cook the onions for another 45 minutes, string every 5-10 minutes to prevent them from burning. If they are burning instead of caramelizing, turn the heat to low and stir more frequently. They should be fragrant and turn a deep golden brown. The size will reduce drastically.
  3. Add Flour, Sherry, and Wine: Turn the heat back to medium and stir the flour into the onions and cook for 1 minute. Slowly stir in the broth, sherry, and wine. Then bring to a simmer. Simmer until the soup begins to thicken and reduce, about 4-5 minutes. Stir in the thyme. Adjust the salt as needed.
  4. Toast Baguette: While the onions cook, toast the pieces of bread in the oven. Brush both sides with olive oil then bake at 350 degrees Fahrenheit for 6-8 minutes, flipping the bread halfway through. Remove from the oven and set aside.
  5. Broil and Serve: Ladle the soup into four oven-safe bowls. Place a slice or two of toasted bread on top of the soup and cover with cheese. Place the bowls on a large sheet pan and broil until the cheese has melted and started to turn brown and bubbly, about 2-3 minutes. Keep a close eye on them as they broil, as some broilers can cook faster than others. Serve immediately.
Onions caramelizing in a pot.

Tips for Success

Use these extra tips and tricks to make sure you end up with French onion soup worthy of your favorite fancy restaurant!

  • Use Your Favorite Kind of Onions: You can use yellow onions, red onions, sweet onions, white onions…pretty much any kind or combination! 10 cups will seem like a lot, but I promise they cook down a ton.
  • Alcohol Substitutes: Instead of sherry and wine you can use cooking sherry and white wine, or additional beef broth. But the two wines add a really great depth of flavor that adds a lot to the soup so I encourage you to use them!
  • Keep an Eye on Your Onions: Make sure to watch the onions, you don’t want them to burn. If they start to burn, turn the heat down a bit and continue to stir.
  • Make Sure to Season as You Go! Season the onion. After you add the broth and wines, season again. After the broth has simmered with thyme, taste for seasoning again. Everyone’s palate is different and what I think is too salty or not salty enough may be different for yours.
  • Don’t Leave Your Broiling Cheese Unattended! Cheese burns FAST. You really need to keep an eye on the soup when it’s under the broiler or you can quickly have a bad situation on your hands.
5-photo collage of the onions being sauteed, combined with the other ingredients, and added to a bowl topped off with baguette and gruyere cheese.

Can I Make French Onion Soup in Advance?

Yes! In fact, please do! Make the soup, sans the bread and cheese from start to finish. Cool completely and store in an airtight container in the fridge or the pot with a lid. It will stay good for 3-4 days. Shred the cheese and store it separately. When you’re ready to reheat, place the pot back on the stove and bring to a boil. Prepare the soup as directed.

A bowl of French onion soup.

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  • Heat a large heavy-bottomed pot over medium heat. Add the butter and let it melt. Add the onions and salt and stir.

  • Let the onions sautee for 5-10 minutes, until they begin to turn translucent. Reduce the heat to medium-low and continue to cook the onions for another 45 minutes, string every 5-10 minutes to prevent them from burning. If they are burning instead of caramelizing, turn the heat to low and stir more frequently. They should be fragrant and turn a deep golden brown. The size will reduce drastically.

  • Turn the heat back to medium and stir the flour into the onions and cook for 1 minute. Slowly stir in the broth, sherry, and wine. Bring to a simmer. Simmer until the soup begins to thicken and reduce, about 4-5 minutes. Stir in the thyme. Adjust the salt as needed.

  • While the onions cook, toast the pieces of bread in the oven. Brush both sides with olive oil then bake at 350 degrees Fahrenheit for 6-8 minutes, flipping the bread halfway through. Remove from the oven and set aside.

  • Ladle the soup into four oven-safe bowls. Place a slice or two of toasted bread on top of the soup and cover with cheese. Place the bowls on a large sheet pan and broil until the cheese has melted and started to turn brown and bubbly, about 2-3 minutes. Keep a close eye on them as they broil, as some broilers can cook faster than others. Serve immediately.

Originally posted on December 13, 2019

Updated on December 11, 2023

Serving: 1bowl of soupCalories: 621kcalCarbohydrates: 57gProtein: 28gFat: 29gSaturated Fat: 17gPolyunsaturated Fat: 2gMonounsaturated Fat: 8gTrans Fat: 0.3gCholesterol: 85mgSodium: 1951mgPotassium: 845mgFiber: 8gSugar: 19gVitamin A: 867IUVitamin C: 32mgCalcium: 725mgIron: 3mg

Nutrition information is automatically calculated, so should only be used as an approximation.

About Alyssa Rivers

Welcome to my kitchen! I am Alyssa Rivers and the food blogger behind The Recipe Critic. The blog launched in 2012 as a place to share my passion for cooking. I love trying new things and testing them out with my family. Each recipe is tried and true, family-tested and approved.

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