This French onion soup recipe is an easy take on an elegant classic without compromising on any of its rich, buttery goodness. Served with French bread and topped with melty cheese, it’s an effortless comfort food
Easy Crockpot French Onion Soup
Full of rich and intense flavors, this crockpot French onion soup is an effortless version of the elegant French classic. When all you have to do is throw everything into the pot and then let the soup cook itself, French cuisine might not seem so intimidating anymore.
With a deep caramelized flavor from slowly cooked onions and a hint of sugar, this broth-based recipe has a complex flavor profile without making the steps to get there any harder. Don’t forget the thyme! Its aroma pairs beautifully with the soup’s buttery goodness.
Topped with a slice of French bread and lots of melty Gruyere cheese, this soup is an ode to French flavors. Easily made in the crockpot and frozen for future cravings, this recipe is the kind of pick-me-up soup your weeknights were missing.
What You’ll Need
This crockpot French onion soup is loaded with classic French ingredients like wine, thyme, and butter. Check the recipe card at the bottom of the post for full ingredient amounts. For more soup inspiration, go through my Creamy Tortellini Soup and Italian Wedding Soup recipes.
- Sweet onions – You can use yellow onions, but increase the sugar to 1 teaspoon.
- Unsalted butter – If you use salted butter, reduce the salt in the rest of the recipe.
- Sugar – Any kind of sugar (except powdered) will work.
- Salt and ground pepper
- Fresh thyme – Don’t skip this one. It’s super important for the soup’s signature taste.
- Bay leaf
- Low-sodium beef broth – This will make the richest soup, but chicken broth is a good alternative. For a vegetarian version, use veggie stock.
- Dry white wine – Don’t use any sweet wines.
- French bread
- Gruyere cheese – Feel free to use Swiss cheese instead.
How to Make French Onion Soup in Your Crockpot
Crockpot French onion soup is all about throwing everything into the slow cooker and letting the magic happen.
- Fill the crockpot. Place sliced onions in a 6-quart slow cooker. Stir in melted butter, sugar, salt, and pepper. Top with thyme and bay leaf.
- Cook it. Cover the crockpot with the lid and cook on LOW for about 8 hours, or until onions are browned and caramelized. Stir halfway through.
- Add the broth. Once onions are caramelized, stir in the beef broth and wine. Taste for salt and pepper and season accordingly.
- Continue cooking. Cover again and cook on LOW for 4 hours, or on HIGH for 2 hours, or until heated through. Remove and discard thyme and bay leaf.
- Continue cooking. Cover again and cook on LOW for 4 hours, or on HIGH for 2 hours, or until heated through. Remove and discard thyme and bay leaf.
- Serve. Ladle soup into ovenproof bowls. Top the bowls with a slice of french bread and cheese. Broil in the oven until cheese is melted, about 2 to 3 minutes. Enjoy.
Tips for Success
Making crockpot French onion soup just got a whole lot easier with these tips.
- Watch the onions. There’s a fine line between golden, caramelized onions and burned onions. Keep an eye on the pan and remove it from the heat once the onions have caramelized, otherwise, your soup will taste bitter.
- Start it on the stove. Combine onions, butter, sugar, salt, and pepper in a large skillet, and cook the onions for about 25 minutes, or until browned and caramelized. Transfer the onions to the slow cooker, add in beef broth, wine, thyme, salt, and pepper, and cook for 6 hours on LOW. When the soup is ready, ladle it into ovenproof bowls, place a slice of baguette in each bowl, top with shredded cheese, and broil for a couple of minutes, or until the cheese is melted.
- Use croutons. Don’t worry if you’re out of French bread, you can top it with your favorite croutons for the same texture.
Serving Suggestions
This crockpot French onion soup is the perfect starter for all your fancy (but easy) meals. I love to serve it with my Easy Rib Eye Steak Dinner or Grilled Scallops as main dishes. Paired with Fluffy Couscous with Asparagus and Golden Raisins and Caponata, it’s the ultimate show-stopping dinner.
How to Store & Reheat Homemade French Onion Soup
Once fully cooled, refrigerate this crockpot French onion soup in an airtight container for up to 4 days. To reheat it, pop it into the microwave for 1-2 minutes or until warm. You can also heat it in a pot over medium heat for 5-7 minutes.
Can I Freeze This?
Yes! Transfer this crockpot French onion soup in serving-size portions in freezer-friendly bags or containers. Freeze the soup for up to 3 months. Let it thaw in the fridge overnight a day before serving. Reheat it as usual.
More Soup Recipes to Try
- Slow Cooker Creamy Cauliflower Soup
- Slow Cooker Vegetable Soup
- Slow Cooker Vichyssoise Soup (Leek and Potato Soup)
Crockpot French Onion Soup
Ingredients
- 6 sweet onions,
- 4 tablespoons unsalted butter, melted
- 1/4 teaspoon sugar
- 1/2 teaspoon salt
- 1/2 teaspoon fresh ground pepper
- 4 to 6 sprigs fresh thyme
- 1 bay leaf
- 6 cups low sodium beef broth
- 1/2 cup dry white wine
- salt and pepper, to taste
- 6 slices french bread optional
- 1 1/2 cups shredded gruyere cheese, optional
Instructions
- Place sliced onions in a 6 quart slow cooker.
- Stir in melted butter, sugar, salt, and pepper.
- Top with thyme and bay leaf, COVER and cook on LOW for about 8 hours, or until onions are browned and caramelized. Stir half way through.
- Once onions are caramelized, stir in the beef broth and wine.
- Taste for salt and pepper and season accordingly.
- Cover and cook on LOW for 4 hours, or on HIGH for 2 hours, or until heated through.
- Remove and discard thyme and bay leaf.
- Turn the oven-broiler on High.
- Ladle soup into ovenproof bowls.
- Top the bowls with a slice of french bread and cheese.
- Broil in oven until cheese is melted, about 2 to 3 minutes.
- Serve.
Notes
- Combine onions, butter, sugar, salt, and pepper in a large skillet, and cook the onions for about 25 minutes, or until browned and caramelized.
- Transfer the onions to the slow cooker, add in beef broth, wine, thyme, salt, and pepper, and cook for 6 hours on LOW.
- When soup is ready, ladle it into ovenproof bowls, place a slice of baguette in each bowl, top with shredded cheese, and broil for couple minutes, or until cheese is melted.
Nutrition
Nutritional info is an estimate and provided as courtesy. Values may vary according to the ingredients and tools used. Please use your preferred nutritional calculator for more detailed info.
This was so good! I threw in some leftover pulled pork that I needed to use up. So good! It would have been good without it too! Thanks for the recipe!
I am very glad you enjoyed it! Thank YOU! 🙂
Love how easy this is to make in the slow cooker! Such a hearty and filling comfort food dinner for the family!
I made this using my own stock it is delicious !!!
My husband will go crazy for this onion soup!
Craving this for dinner! Looks great!
It’s rainy and cold here and I am totally craving a big bowl of this soup! Sounds absolutely amazing!
My husband loves this soup and always orders it when we go out. Can’t wait to make this at home for him!
This soup looks so amazing!
Hi! How can i substitute wine? Can’t use it for muslim 🙁
Hi Kate!
You can use apple juice and a tablespoon of lemon juice. I hope that helps! Have a great day!
Anyone tried freezing this soup?
No, I’ve never tried freezing it. I know it stays good in the fridge for a couple of days.
Just an idea…I am making the soup as I type! I used a vegetable slicer for the onions, no tears! Also another tip is breath through your mouth not your nose, it works! 🙂 thanks for the yummy recipe!
Thanks SO much, Audra, for sharing those tips! Believe me when I say that I will be using them asap – I hate the whole onions/crying thing. 😀
Hope you enjoy the soup!!
♥ Kate
Great tips!! Thanks, Audra!
Did you enjoy the soup?
One of my husbands all time favorite soups – gorgeous!
We need some of this soup and Sandra’s onion tea (I’ve heard of that before) for my kiddos too. This is one of my favorite soups. Yours looks fantastic!
Hope your little one feels better soon! I had a sick household yesterday {hubby & both kids}, so I made them a big batch of tomato soup. French Onion is one of my favorites & this looks divine!!
Yup your granny is right , onions are full of vitamins C and I make tea for my kids when they are sick with onion..I know sounds disgusting but with some honey and lemon you could never tell it is with onions(w/peel). I hope your kiddos feel better soon! :*
Your onion Soup looks fantastic, loving your presentation and recipe is tasty too!
I just love the idea of making this in the slow cooker! One of my favorite soups.
I hope the little one is feeling better and that it’s not spreading around the house. 🙁 Today is a day of coincidences I think. I’m catching up on blog reading tonight and the last post I read was also for French onion soup – which I’ve never had. And even more coincidental, I saw it on a menu this morning and decided I need to try it. I’m loving this slow cooker version – my kind of meal! 🙂
This is a great idea that I’ve got to try. My brother once showed up with a scuba mask to chop onions. It seemed to work well for him.
That is hilarious! Lol!
My all time favorite soup….besides corn chowder….is French onion soup!!!! I love your recipe:-) My grandfather makes homemade onion soup that is truly to die for:-) I hope your babies are feeling better, Hugs, Terra
Oh! I hope your lumpy feels better soon 🙁 That’s always a terrible thing to have to see.
Do love this soup though! Winter is fast approaching in Cayman with temps dropping into GASP the 70s! Believe it or not, that totally calls for slow cookers. Bookmarking this bad boy!
I love you made this in a slow cooker! Yum. I could seriously eat an entire pot of this soup alone…
I think I love your idea of changing the beef broth to chicken. I prefer chicken flavor and I will definitely give this recipe and cooking method a try. Onions are very healthy…. and I love them. 🙂
I hope your sweet baby gets well quickly… I know it’s emotionally and physically tolling for parents when they are sick. My kids have coughs now and I wish I could magically get them better.
Have a good weekend. ~ Ramona
My husband and I looooooooooooove French onion soup and we order it when it’s available. We’ve made once at home but it’s been a while. I don’t own a slow cooker but maybe I can cook slowly on a cast iron? Looks so delicious!