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French Onion Soup

This traditional French Onion Soup recipe has warm baguettes topped with hot, melted Gruyere cheese. High quality beef broth, a splash of wine, and perfectly caramelized onions are the secrets to this classic recipe. PLUS, check out how you can prepare this recipe in the Crock Pot.

Two slices of baguette with melted cheese in a bowl of french onion soup and thyme on top.

French Onion Soup

In case you didn’t know, I am a soup fanatic. And there are so many different ways there are to make a traditional, homemade french onion soup recipe.  I have tried them all, I’ve researched a lot, and I’ve finally got this recipe totally nailed down.

The secret to making the best French Onion Soup is to properly caramelize the onions and to use high-quality ingredients. That means using good butter, wine, broth, fresh baguettes, and cheese.

But don’t worry- I’ve offered great substitution options if you prefer not to use alcohol or would like more budget-friendly cheese options. I’ll even show you how the Slow Cooker can help you caramelize those onions!

Here are all of my KEY tips on making this recipe:

 

Use a Combination of Yellow and Sweet Onions

  • Each type of onion adds a different element of flavor. Combining the two allows you to enjoy the best of what each has to offer.
  • I like to use 2 sweet (vidalia) onions and 4 yellow onions, they weigh a solid 5 pounds total.
  • Use a madoline slicer to cut the onions quickly and evenly.

Use Dry White Wine

  • I have tried several different wines for this recipe and I find dry white wine to be the best.

Best Dry White Wines for Cooking:

  • Sauvignon Blanc
  • Pinot Grigio
  • Unoaked Chardonnay

If you prefer to make this without wine:

  • You can substitute 3 Tablespoons white wine vinegar + chicken or beef broth to make 3/4 cup.

Best Cheese For French Onion Soup

  • Gruyere cheese is best.
  • Other cheese options include Comte, Emmental (Swiss), Provolone, or Mozzarella.

Use High Quality Beef and Chicken Broth

How to Caramelize Onions

Caramelizing onions is very easy, it takes patience more than skill. Follow the simple steps below and the rest will take care of itself.

Don’t cut the onions too thin

  • You want 1/4 inch slices, as they will shrink down and you don’t want them to be too thin or stringy.

Coat the onions generously in butter.

  • Use a set of tongs makes them easy to toss around in the pot.

Cook them low and slow

  • Cook the onions over medium-low heat. This process takes some time but the end result is well worth it.

Use more onions than you think

  • Onions made up of over 80% water. They shrink down considerably as they cook, as you will see below.
  • I use 5 pounds in this recipe.

Watch These Onions Caramelize. Each Photo is 20 minutes apart.

Onions in a soup pot that are freshly cut and beginning to cook down in order to make French Onion Soup.

Onions in a soup pot for French Onion Soup that are beginning to soften. Onions in a pot that are beginning to caramelize and turn a light brown. Step by step photos of how to caramelize onions, this is the end of process where they are caramelized and brown.

Caramelizing Onions in the Crock Pot

The benefit of caramelizing the onions in the Crock Pot is that you don’t have to stir them while they reduce and you can get most of the work done overnight. They’ll need to cook on low for 10 hours.

Note: To fully caramelize them, you will need to transfer them to a pot on the stove at the end with some additional butter and some of the juices from the Crock Pot over medium-high heat for 10-15 minutes. You will then finish the soup on the stove top as well.

  • Melt 4 Tablespoons of butter in the Crock Pot. Add the onions and toss to coat. Cook on low for 10 hours.
  • Melt 2 Tablespoons of butter in a large pot on the stove over medium-high heat. Wait until it begins to foam. Add the onions and cook for 10-15 minutes.
  • Decrease heat to medium. Add the white wine and cook for an additional 2-3 minutes. Pour in the beef broth, chicken broth, Worcestershire sauce, and add the bay leaves and thyme.
  • Simmer for another 45 minutes on the stove with the lid cracked. OR, transfer back to the Slow Cooker and cook for 2-3 hours on high or 4-6 hours on low.

Instant Pot Method

Yes, it’s true! You can make this in the Instant Pot! (As featured on MSN.)

Make-Ahead Method

  • There is probably no better soup to make ahead of time than this. This soup can be stored in an airtight container for up to three days prior to serving.
  • The soup can be reheated on the microwave, Slow Cooker, or stove top, and the baguettes and cheese can be toasted/melted separately and added to the soup once ready to serve!

Freezing

This is a great freezer meal.

  • Let it cool prior to freezing and store it in an airtight container.
  • It’s best if used within 3 months of freezing.
  • Freeze only the soup, don’t include bread/cheese with it.

Overheat shot of a hand holding a white bowl filled with french onion soup topped with two cheesy baguettes.

Try These Next!

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A mug of French Onion Soup topped with 2 slices of cheesy baguettes.

French Onion Soup

4.96 from 81 ratings
This traditional French Onion Soup has warm baguettes topped with hot, melted Gruyere cheese. High quality beef broth, a splash of wine, and perfectly caramelized onions are the secrets to this classic recipe.

Ingredients

  • 4 large yellow onions,, see notes for pound conversion
  • 2 large sweet onions, Vidalia
  • 6 Tablespoons butter
  • 2 sprigs fresh thyme
  • 2 Bay leaves
  • ¾ cup dry white wine, Chardonnay or Pinot Grigio
  • 3 tablespoons flour, optional
  • 4 cups beef broth, high quality is key
  • 1 beef bouillon
  • 1.5 cups chicken broth
  • 1 teaspoon Worcestershire sauce
  • Salt/Pepper, to taste
  • 1 baguette
  • 3 Tablespoons olive oil, optional
  • 6 slices Gruyere cheese

Instructions

  • Slice the onions into ¼-inch slices, (no thinner). They'll reduce in size quite a bit and you don’t want them to be too stringy. (Using a mandoline slicer makes this much easier).
  • Melt the butter in a large soup pot or dutch oven over medium-low heat. Wait until it begins to foam, this allows water to evaporate out, leaving the butter more clarified and smooth.
  • Add the onions and use tongs to toss and coat them in the butter. Leave them uncovered as they cook.
  • The onions will caramelize slowly, roughly 1 hour. Stir them every 10-15 minutes. As the onions caramelize, they may leave some brown residue at the bottom of the pot. Add a splash of wine and use a silicone spatula to 'clean' the bottom of the pot. Repeat as needed throughout the cooking process
  • When the onions are nearly done, sprinkle flour over them and cook for 2 minutes. Add any remaining wine and increase the heat to medium-high. Toss the onions more frequently. They are done when they are richly brown and sweet.
  • Add the beef broth, beef bouillon, chicken broth, Worcestershire sauce, bay leaves and thyme. Simmer over medium heat for 45 minutes with the lid cracked.
  • While the soup simmers, preheat the oven to 350° F.
  • Slice the baguette into ½ inch thick slices. Brush the tops with olive oil and bake for about 5 minutes.
  • Increase the oven temperature to 450° F. Top each baguette with cheese and bake in the oven until the cheese melts and begins to bubble and brown.
  • Remove the bay leaves and thyme stems. Season to taste with salt and pepper.
  • Ladle the warm soup into each bowl and top each of them with the warm baguettes. Serve!

Notes

  • You should use about 5 pounds of onions (total) for this recipe.

  • If you prefer not to use Wine, you can substitute 3 Tablespoons white wine vinegar + chicken or beef broth to make 3/4 cup.

  • Other cheese options include Comte, Emmental (Swiss), and/or Provolone.

Crock Pot Method:

Note: The stove top does come into play with this method as the heat is needed to fully caramelize the onions at the end. However this method allows you to almost fully caramelize the onions overnight without stirring.
  • Melt 4 Tablespoons of butter in the Crock Pot. Add the onions and toss to coat. Cook on low for 10 hours.
  • Melt 2 Tablespoons of butter in a large pot on the stove over medium-high heat. Wait until it begins to foam. Add the onions and cook for 10-15 minutes.
  • Decrease heat to medium. Add the flour and cook for 2 minutes. Add the white wine and cook for an additional 2-3 minutes. Pour in the beef broth, chicken broth, Worcestershire sauce, and add the bay leaves and thyme.
  • Simmer for another 45 minutes on the stove with the lid cracked. OR, transfer back to the Slow Cooker and cook for 2-3 hours on high or 4-6 hours on low.
Check out my Instant Pot version!

Nutrition

Calories: 509kcal, Carbohydrates: 40g, Protein: 16g, Fat: 30g, Saturated Fat: 14g, Polyunsaturated Fat: 2g, Monounsaturated Fat: 11g, Trans Fat: 1g, Cholesterol: 61mg, Sodium: 1284mg, Potassium: 479mg, Fiber: 4g, Sugar: 10g, Vitamin A: 638IU, Vitamin C: 16mg, Calcium: 377mg, Iron: 3mg
Did you try this recipe?Mention @TheCozyCook on Instagram or tag #thecozycook!

This classic French Onion Soup has a rich, silky broth made from thinly sliced onions, butter, white wine, beef broth, fresh thyme and bay leaves. All topped with a toasted baguette and hot, bubbly Gruyere cheese. | The Cozy Cook | #soup #frenchonionsoup #onions #recipe #easyrecipes #winterrecipes #gruyere

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214 comments on “French Onion Soup”

  1. Soup was delicious!! Will definitely use this recipe again.

  2. we are making this for Christmas Eve this year–it’s amazing!!!

  3. I’m SO glad I tried this soup. It was awesome. I used the fresh thyme and it made a huge deference. I could taste it perfectly and it wasn’t overpowering. I feel like the sprigs are the key to making it taste elevated and fresh. Question though. Does the calorie/nutrition information reflex the soup with the bread and cheese?

    • Hey Danielle! I am sooo happy that you loved this soup, this is definitely one of my favorites as well and I agree, the thyme really elevates it without being too much. The nutritional information includes everything in the ingredients list, included the bread and the cheese! 🙂 Thank you so much for the wonderful review, I really appreciate it! -Stephanie

  4. This recipe is so delicious, love it!

  5. I made a fancy Christmas meal for my family. It was wonderful everyone loved it. So I said ok I will do a fancy meal again if you want me to. Yes we do but can you make the French Onion Soup!!!!!!!!!!
    It is so good we all love it. The rich flavor and just a special soup. I do use beef consommé too. Big hit with the family!!!! Thanks you nailed it!!👍🏻♥️♥️

    • Hey Rachel!! I’m soooo happy that you enjoyed the soup, I love the “fancy meal” idea, that’s fun!! Thank you so much for taking the time to leave a review, I really appreciate it! -Stephanie

  6. Delicious flavor! Only trouble was I halved the recipe for fewer servings and all of the stock liquid ended up evaporating in the last step so I had to add more liquid last minute before serving — should I have reduced the cooking time given I reduced the volume?

    • Hi Katy!! Yes, if you use less liquid, you’ll need less reduction time, (and more reduction time for more liquid)! I’m so glad that you loved the flavor however! 🙂

  7. This recipe is amazing!! I made it but did not have the Worcestershire sauce or the beef bouillon and substituted 2 teaspoons of regular salt for the saltiness. It was easy to make, had a fabulous flavor and tastes like it came from an upscale restaurant! I will definitely make it again! My son says it makes a great comfort food! I’m glad I found this recipe on Pintrest. I will definitely try your others dishes, which I’m sure will be great too! Thanks a bunch!

    • Thanks so much for the great comments! I’m so happy you enjoyed this as much as I do💗

    • If you don’t have worcestershire sauce, balsamic vinegar is a great swap instead. It’s what I’ve always used in French onion soup, though the recipe I found years ago that used it had suggested to add the balsamic vinegar during the step where you caramelize the onions. Makes them very rich.

      That one used just beef broth and wine, I like the idea of having a mix of chicken and beef with the wine. I’ve used that combo with sauces and it adds a nice depth of flavour even if its subtle.

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