Slow Cooker French Onion Soup is one of our favorite meals to come home to! As with any traditional French onion soup, this recipe features a beefy broth loaded with caramelized onions and herbs and topped with an amazing Gruyere cheese topping!
© SpendWithPennies.com
Crockpot French Onion Soup
French Onion Soup is one of my husband’s all-time favorites. It’s the perfect meal for any soup lover!
For me it’s all about the bread and cheese… all soaked in that rich herby onion broth and then broiled until the cheese gets all hot and bubbly. Scooping up the first bite of that ooey gooey cheese is like a little taste of heaven.
While French Onion Soup is good, I do think that a good broth takes a long time to develop great flavor which is something I love about this recipe.
In this recipe, the onions and broth have the chance meld in the slow cooker all day long creating a rich and flavorful soup. Not to mention, I’m a huge fan of slow cooker meals because I love coming home to dinner ready to go!
It just seems to make the evening run that much smoother, at least in my house with activities, homework and soccer practices!
Why do they Call It French Onion Soup?
French onion soup actually originated in France in the 18th century and has been a traditional soup of France ever since. This soup is most often served as a starter, however, we love to enjoy it (with extra bread and a salad) as a meal.
How do you Make French Onion Soup from Scratch
To make french onion soup completely from scratch you’d want to start with your own homemade broth or stock. While I often make chicken broth from scratch for this recipe I usually use a lower sodium store-bought broth. Either will work just fine.
Caramelizing the onions does take a little bit of time but it’s totally worth the effort. You want them translucent and golden without browning or crisping them so low and slow heat is the way to go with these! You don’t have to stir them constantly but you do want to make sure they aren’t cooking too quickly.
While I caramelize them on the stove top for convenience, you can actually caramelize them right in your slow cooker too but it does take 8-10 hours! If you get them started the night before, you can wake up to caramelized onions, add the remaining ingredients and you’re good to go!
How to Caramelize Onions in the Slow Cooker
Combine 3lbs sliced onions, 1/2 cup unsalted butter and 1/2 teaspoon salt. Stir and cook on low 8-10 hours. (You would need half of these onions for this recipe but can add more if you like. You can freeze the other half to add to mashed potatoes, casseroles, soups and more). (Note you do not need brown sugar if you use this method, the onions have enough natural sugars).
What is the Best Onion to Use in French Onion Soup
When making French onion soup, you’ll want an onion that will caramelize well and have the right amount of sweetness.
I find using regular white onions provides the best results as sweet onions can overpower the broth and tend to create a soup that is too sweet.
If you happen to have only sweet onions on hand, I would suggest eliminating any sugar from the recipe.
What kind of cheese is best for French Onion Soup?
The bread and cheese topping is one of my favorite parts of this recipe. Using Gruyere and Emmental cheeses really make this dish amazing, however, you can substitute mozzarella/ parmesan/ swiss if it’s all you have on hand.
I love to ladle this into bowls, add the cheese and broil, however, you can simply place the bread & under a broiled on a pan and add it to your bowls if you prefer.
Serve this French Onion Soup with a side salad and some extra bread for a delicious dinner!
More Crockpot Soups You’ll Love
- Slow Cooker Chicken Pot Pie Soup – Comforting and creamy.
- Crock Pot Cabbage Roll Soup
- Slow Cooker Chicken Enchilada Soup
- Crockpot Chicken Noodle Soup – Great for leftovers!
- Slow Cooker Cajun Bean Turkey Soup Recipe
- Easy Crock Pot Ham and Potato Soup – Favorite recipe!
Equipment
Ingredients
- 3 large white onions sliced
- 3 tablespoons butter
- 64 ounces beef broth I use reduced sodium
- 1 tablespoon Worcestershire sauce
- 1 clove garlic minced
- ⅓ cup dry sherry
- 4 sprigs fresh thyme or 1 teaspoon dried thyme
- 1 bay Leaf
- 8 slices French bread * stale or dry is best
- ¾ cup shredded Gruyere cheese
- ½ cup shredded Emmental cheese
- 6 tablespoons shredded Parmesan cheese
Instructions
- In a large non-stick pan, cook onions, and butter over medium-low heat until golden and caramelized. (About 20 minutes).
- Once golden, add to the slow cooker along with the remaining ingredients except for bread and cheese.
- Cook on low for 6 to 8 hours.
- Remove and discard bay leaf and ladle the soup into bowls. Top with dry bread slices and cheeses. Broil 2 to 3 minutes or until cheese is melted and browned.
Video
Notes
Nutrition Information
Nutrition information provided is an estimate and will vary based on cooking methods and brands of ingredients used.
Course Dinner, Lunch, Soup
Cuisine American, French© SpendWithPennies.com. Content and photographs are copyright protected. Sharing of this recipe is both encouraged and appreciated. Copying and/or pasting full recipes to any social media is strictly prohibited. Please view my photo use policy here.
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Amazingly delicious. Everyone loved it! I caramelized 3 large yellow onions on the stovetop for 45 mins. Then added everything but the bread and cheeses to a pot and simmered for 4 hours on stovetop. When ready to eat, I laid 6 crostini on top of broth and added gruyere, parmigiano reggiano and pizza blend and broil for 10 mins. Will make whenever I have to use up a bunch of onions.
So glad everyone loved it Kate! Thanks for sharing your stove top method!
Made this a bunch of times but never same twice. I used white, yellow, and sweet onion. This time I used sweet onions a lot more butter and 1/4 cup xabernet sauvignon wine and was absolutely amazing.
That sounds delicious Rob! So glad to hear you love this recipe!
Thanks for the easy, no fuss recipe. In my personal taste, it was a little too sweet and the condensation from the crock pot lid made the soup watery. After the six hours, I transferred the soup to a stock pot and boiled it down a bit. Still sweet, but not as watery. I will definitely make this again, but with less brown sugar and on the stove. Other than that, good color, good amount of onions and thyme. Thanks again!
If you put a large piece of heavy grade aluminum foil on top of pot and then the cover, the condensation will go onto the foil. Make sure to fold the edges of the foil up, and remove cover as little as pssible.
All ingredients are perfect except garlic…French onion soup does not include garlic at all…garlic is vastly overrated as an ingredient because it kills the taste…
Feel free to leave the garlic out if that’s your preference Jay. Enjoy!
Just finished having the French onion soup. It was unbelievably delicious
Gave some to our daughter for work and my husband has not stop thanking me and telling me how delicious it was, wants me to make it again tomorrow night
I used croutons and sliced Swiss cheese, it was so hot the soup melted the cheese so I didn’t do the broiling part . Thank you for the recipe
You’re welcome Dianne! Glad to hear your family enjoyed it so much!
If I cut the recipe in half, will it fit in a 2qt crockpot? It’s just me in my house, and I only have a small crockpot.
I haven’t tried it but I think it should work just fine!
I did make this and it was great!
Glad to hear you loved it Mike!
Would love to make this but do not need that much! Way too much! How would I cut it down? Sounds do yummy!
You can make the recipe as written and freeze the soup before adding the bread/cheese. :)
FANTASTIC!!!
are yellow onions the same as white onion? can’t wait to make this!!!
White and yellow onions are a little different. White onions tend to have a sweeter flavor than yellow onions. They are often used interchangeably in recipes.
Wow Holly, thank you for writing this crock pot recipe. I actually don’t like onions in food and was recently convinced of its goodness. I’m traveling right now so I can’t try this out. Will be sharing with my friends, thanks.
You’re welcome Coeba!
Hi! I soooo love this! Made this last night only thing I did different because I told my kids it’s onion soup they went blaa was I chopped up 3 lb of chicken thighs and put it in with the onions and the rest of they ingredients ! It came out so hearty and heavily! !! The family wants me to make this more!!! For the people who were worried about the Sherry how about alcohol content I bought cooking Sherry at the supermarket for $3 it does at such flavor!!! for the cheese I used freshly grated three cheese blend from my supermarket it had parmesan Asiago and Romano. I had the soup and soup Crocks put the bread in in the cheese on top and had them broiled in the oven till the cheese was brown and crispy! I highly recommend this recipe
So glad you loved it! My family would love chicken, I’ll have to try it!
Just FYI – cooking sherry also contains alcohol. The difference is that cooking sherry has had salt added to it so lasts longer. It is not drinkable (for those that might otherwise be tempted.) and it comes in small bottles. However, during the cooking and heating process, ANY form of alcohol will evaporate and be boiled off, leaving just the flavor.
Hi Holly,
I love French Onion soup so I’m trying your recipe in the crockpot today. I just have a question. When I cook the onions on the stovetop with the butter and brown sugar, do I add the juice that was created from the butter and brown sugar to the crockpot with the onions ?
You can add the juice if you’d like, there should be very little liquid left in the pan.
Thanks for posting this recipe. I made it today, and it was delicious!
I’m so glad you loved it!
This was my first time making French Onion Soup and I am extremely pleased! Even my husband had a second bowl and he’s not had French Onion Soup before. I could not find Emmental cheese (not even sure what it is) but it tastes great without it. The ingredients blended well and the flavor rivals restaurant soups. Definitely a winner for a cool 20° night on Texas…or anywhere!
This is soooooo good. I do up a large slow cooker FULL of onions then freeze half to make it again in a couple of weeks,
Freezing the onions is a great time saver! So glad you enjoyed it!
Made your soup with red onions and cooking sherry which has salt in it, then used the low sodium beef broth. Fantastico! Will be making it again this winter. Thank you for sharing.
I am so glad you enjoyed this recipe!
I’m a french onion soup addict and a bit of a snob to boot. This is the best onion soup EVER! I caramelized the onions in the slow cooker and used all of them in the soup. Totally awesome!
Yay Kim, so glad you loved it!
How do you caramelize in the slow cooker. I want to try this recipe in one?
The directions for caramelizing in the slow cooker are above within the post.
I used salted butter and ommitted salt. Took 8 hours in my slow cooker to get onions translucent and golden. I use cooking sherry. Delicious. Kathleen R. Calgary Akberta
I used 3lb of onions and carmelized them in the slow cooker overnight. My slow cooker only took 8 hours to get them translucent and golden. I used salted butter and did not use salt. Cooking sherry works very well.
Delucious. Kathleen R. Calgary, Alberta