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French Onion Soup makes a comforting, classic bowl of soup! Made with caramelized onions, a slice of crusty bread, and melty, delicious cheese! Includes stovetop and slow cooker methods!
French Onion Soup is one of my favorite soups, especially when the temperatures outside drop – even just a little.
French Onion Soup Recipe
There’s something so very comforting about breaking through the cheesy, French bread exterior to get to the delicious brothy soup underneath!
It has always been one of those soups that I would look forward to having at restaurants, but I didn’t know how to make at home when we first married.
It wasn’t until our third Christmas together that I tried to make it. We were hosting the soup course of a Christmas progressive dinner, and my husband requested it. It turned out perfectly and continues to be a go-to recipe for me.
How to Make French Onion Soup Recipe
French Onion Soup Ingredients
French onion soup includes a few classic ingredients for its signature flavor and presentation. You’ll need:
- Yellow onions: you’ll want to thinly slice your onions for this soup. They will be caramelized and add a sweet, delicious flavor to this recipe.
- Butter: It helps to brown the onions and adds flavor to the soup.
- Salt: Helps the onions to release their juices and balances the flavor.
- Olive oil: The onions cook with a bit of olive oil.
- Garlic: A clove of minced adds flavor.
- Beef stock or broth: French onion soup is a broth-based soup, and I prefer to use a mixture of beef and chicken stock or broth in my soup.
- Chicken stock or broth: See the note above under beef stock.
- French bread: Lightly toasted and served on top of the soup. Yum!
- Cheeses: Grated Gruyere and Parmesan cheese top the soup.
Make the French Onion Soup
Caramelize Onions: Slice onions thinly. Add onions, salt, and butter to Dutch oven set over low heat. Stir occasionally until the onions have cooked down and are a caramel color, about 45 minutes to an hour.
Cook garlic. Add garlic and cook until fragrant, about 1 minute.
Stir in stock and simmer. Then stir in the beef and chicken stock. Cover and let simmer for 30 minutes.
Ladle the soup into individual, oven-proof soup bowls. Top with toasted bread and the cheeses.
Place on a lined baking sheet and under the broiler in the oven until the cheeses have melted and browned lightly, about 8 minutes.
The Onions
In my opinion, the most important ingredient in this soup is the onion. Different onions can change the overall taste of your soup, leaving some to think one variety of onion makes for a better soup than others. While it may be a personal preference, through the years, I have tested various types of onions, cooking times, amount of caramelization, etc., to find the recipe that appeals the most – and this is it!
For the onions, there are three varieties that I have tested.
- Sweet Onions – sweet onions, such as Vidalia, give the soup a mildly sweet flavor without a bitter aftertaste.
- Yellow Onions – yellow onions give the soup a lot of flavor with some bitterness.
- Red Onions – red onions give the soup a strong flavor without much sweetness.
Throughout the testing and years of making this soup, I prefer to use sweet onions as I believe it makes the best onion for French Onion Soup.
How to Make Slow Cooker French Onion Soup Recipe
I love to make my French Onion Soup in the slow cooker! It is a simple process that leaves you without babysitting the onions as they caramelize or while the soup simmers.
Slow Cooker French Onion Soup
Caramelize Onions in Slow Cooker: Add your sliced onions to the slow cooker, along with butter and salt. Pop the lid onto your slow cooker and set it on low heat for 10 hours. This is perfect for doing overnight so that you are ready for step two of your soup in the morning!
Make the soup: Once your onions have caramelized in your slow cooker, you are ready to move to step two with your Slow Cooker French Onion Soup! Add garlic, beef stock, and chicken stock. Stir well to combine and cook on low setting for 8 hours.
Broil and serve. When ready to serve, ladle soup into oven-proof bowls and top with bread and cheeses. Place on a lined baking sheet and under the broiler in the oven until the cheeses have melted and browned lightly, about 8 minutes.
There’s something about a comforting bowl of soup that seems to improve any day!
How to Make Ahead and Freeze French Onion Soup
To make ahead: Cook French Onion Soup as directed and ladle it into oven-proof bowls. Cover the bowls and place them into the refrigerator for up to 3 days. When ready to serve, preheat the oven, remove the soup from the refrigerator, and place it into the oven to reheat the soup for 15 minutes. Remove from the oven and top with bread and grated cheeses. Return to the oven and bake as directed.
To freeze: Make the soup without adding the bread and cheese. Transfer to a freezer-safe container and freeze for up to 3 months. To serve, thaw in the refrigerator overnight and then proceed with the recipe as written. If you freeze the soup in individual portions, you can thaw and reheat only what you need.
Other Favorite Cozy Soup Recipes
Here’s my French Onion Soup recipe. I hope you love it as much as we do!
French Onion Soup
Ingredients
- 6 medium yellow onions thinly sliced
- 4 tablespoons butter
- 1/2 teaspoon salt
- 2 tablespoons olive oil
- 1 clove garlic minced
- 8 cups beef stock or broth (64-ounces)
- 1/2 cup chicken stock or broth
- 8 slices French bread toasted
- 2 cups Gruyere cheese grated
- 1/2 cup Parmesan cheese grated
Instructions
French Onion Soup Recipe (Stovetop)
- Add onions, butter and salt to large Dutch oven with olive oil set on low heat until the onions are browned and caramelized, about 1 hour. Add garlic and heat thoroughly, about one minute. Pour in beef stock and wine (or chicken stock). Stir, cover and allow to simmer over low heat for 30 minutes.
- When ready to serve, ladle soup into oven proof bowls and top with bread and cheeses. Place on lined baking sheet and under the broiler in the oven until the cheeses have melted and browned lightly, about 8 minutes.
Slow Cooker French Onion Soup Recipe:
- Add onions, butter and salt to slow cooker. Cook on low setting for 10 hours.
- Add garlic, beef stock and wine (or chicken stock). Stir well to combine and cook on low setting for 8 hours.
- When ready to serve, ladle soup into oven proof bowls and top with bread and cheeses. Place on lined baking sheet and under the broiler in the oven until the cheeses have melted and browned lightly, about 8 minutes.
Video
Notes
How to Make Ahead and Freeze French Onion Soup
To make ahead: Cook French Onion Soup as directed and ladle it into oven-proof bowls. Cover the bowls and place them into the refrigerator for up to 3 days. When ready to serve, preheat the oven, remove the soup from the refrigerator, and place it into the oven to reheat the soups for 15 minutes. Remove from the oven and top with bread and grated cheeses. Return to the oven and bake as directed. To freeze: Make the soup without adding the bread and cheese. Transfer to a freezer-safe container and freeze for up to 3 months. To serve, thaw in the refrigerator overnight and then proceed with the recipe as written. If you freeze the soup in individual portions, you can thaw and reheat only what you need.Nutritional Information
Enjoy!
Robyn xo
Yes – wondering about the Olive Oil too mentioned on the directions of making the soup – how much olive oil or is it in replacement of the butter??
Hi Germaine,
Thanks for mentioning to me – I’ve corrected the ingredients list in the recipe to include the amount of olive oil. Enjoy this – it’s delicious!
Stupid question, I know; but can this soup possibly be made in an Instant Pot ?? Thank you 😊
Hi June!
Not a stupid question at all. 🙂
I’ve not made it yet in the Instant Pot – I hope to give it a test soon.
Thanks!
Slow cooker instructions say 8 hours and 10 hours which is it?
As I explain in my post, this is a two step process in the slow cooker. You cook the onions, butter, and salt in the slow cooker for 10 hours to carmelize the onions. Then you add the garlic, beef stock, and wine to the slow cooker with the onions and cook for another 8 hours. Hope you enjoy the soup, Nicole.
Can the soup be frozen, in appropriate individual portions, once it’s done in the slow cooker and then defrosted as needed, finishing off in the oven with the bread and cheeses?
It can be frozen, Sharon. Hope you enjoy!
It can be frozen, defrosted, and then finished just as you have written, Sharon. Hope you enjoy!
Love all your recipes Robyn yummy,
Thank you so much, Douglas!
Where does the sodium come from? Recipe sounds great
The salt, cheese, beef stock, and French bread all contain sodium. Hope you enjoy the soup, Linda.
Well I made the French Onion Soup for the first time and I can honestly say it is the best soup I have ever tasted!
We had few friends over for dinner and they were begging me for the recipe, thank you for making my dinner party a huge success, can’t wait to try the other recipes!
Thanks, Lisa.
I’ve never made onion soup and want to give it a go. Have spent a good deal of time looking for individual serving containers but most seem so small. Are your Staub cocottes 8 ounce or the 0.5 quart/16 ounce? Anxious to try your recipe! Thank you!
These were the 8 oz Staub cocottes, Betsy. I hope you enjoy the soup.
Thank you!