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.
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
- Some recipes call for using only beef broth, but adding chicken broth creates a greater depth of flavor.
- Homemade or High-quality commercial beef broth is a must. You can also try to purchase a private label from a local butcher.
- Homemade chicken broth is also ideal for this soup.
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 was taken 20 minutes apart.
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.
Try These Next!
Want My Soup Crocks?
(Amazon affiliate link) I bought these oven safe soup crocks just for this soup. They’re very study, handmade, super high quality.
Check out all of my kitchen essentials here.
Get My Free Meal Plan
I’ve got a Free Meal Plan with 7 of my super popular recipes (complete with grocery list)! Sign up for my email list and I’ll send it over now along with weekly dinner recipes!
And follow me on Facebook, Instagram, and Pinterest!
French Onion Soup
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 cube, or 1 tsp Better Than 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.
- The onions will caramelize slowly, up to 2 hours or longer. 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.
I’m so happy I found this recipe, I’ve tried a ton of them over the year’s, this is the one!! Very easy following the recipe, the taste is out of this world! My whole family loved it 🤤 definitely making it again, soon!
Thank you soooo much Colleen!! I had tried a TON of recipes too in the past, often times I ended up disappointed but this one does the trick every time! 🙂 I really appreciate the review, thank you!! -Stephanie
Delicious. My family loved it. I caramelized for 1.5 hrs. I am so proud of myself! Thanks!
Great job!😀 Being patient with caramelizing the onions definitely pays off! Thanks so much for the review!
If I don’t have chicken broth can I just use all beef broth??
Yes you can!
Delicious! I used red wine and caramelized the onions for 1.5 hours total. It’s worth the work for this wonderful recipe. I think Parm is my favorite on the cheese toasts, but the gruyere is great too! 🙂
Thanks so much for the review Summer! Sounds like your hard work paid off!😃 I agree, Parm is definitely a great option for the toast!
I’ve tried several recipes in the past. This, by far, is the best recipe I’ve had (even better than most restaurants). I changed nothing and it is still awesome. I’ve made it now twice and am planning to spice up my 2020 fall season with this amazing recipe. If you like “French Onion Soup”, give this recipe a try. I did not substitute anything. I especially kept the gruyere cheese and the specified onions. I believe this is what makes the recipe great. ENJOY
Thanks so much Betty Ann!!!😀 My father in law is from New York and whenever he visits he demands I make this for him🤣 Thanks so much for the review!
The most delicious French onion soup you’ll ever have! It’s absolutely perfect. Deep complex flavors resulting in a bowl of happiness.
It’s almost impossible to improve on perfection, but I suggest making your own baguettes if you can and we enjoy a combination of Swiss and gruyere for the topping.
Thanks soooo much Brittany!😁 I’m so happy it resulted in a bowl of happiness! Thanks so much for taking the time to leave a review!
Thank you very much for providing the non-alcoholic substitution. I wondered if it would work previously with the white wine vinegar but nice to be sure.
You are so welcome! Enjoy the soup!!!
This was A.M.A.Z.I.N.G.! Will make over and over again!
That’s so great Amanda, I’m so happy to hear that!!! Wooooo! 🙂 Thank you so much for the review!!
This looks so delish!!! Do you think this would be okay if I used a vegetable broth instead of a beef broth? I know that the beef broth will give it the depth of flavor – would you know of spices or other ingredients that would give it that enhancement? My daughters are vegetarian and they will ask me… le sigh…
Hi Susan!! I would recommend using mushroom broth instead of vegetable if possible. And a teaspoon of vegan Worcestershire for some umami! 🙂
I have this on the stove top now! My 2nd time making it. I do splash a good amount of Worcestershire sauce.
I’m so happy that you love the Soup!! Actually I added Worcestershire sauce last time that I made this as well, and it’s super. Enhances some of the other flavors and adds umami! I’ve added it to the ingredient list, thank you for reminding me! Enjoy the soup. 🙂
My only experience with French onion soup is panera’s. My boyfriend has never had it and had nothing to compare it to. But, man, this is SO. GOOD. We both ate way too much in one sitting, but no regrets!
I looovveee French Onion Soup! I love Panera’s Broccoli Cheddar, they definitely know how to make a good soup. I’m glad you enjoyed this recipe!