French onion soup feels fancy, but it doesn't need to be hard. This Crock Pot French Onion Soup delivers deeply caramelized onions, rich beef broth, and melted cheese over toasted bread.
The slow cooker does the onion work for you-no babysitting a soup pot. It works in any size crock pot, from a 2-quart mini to a full-size slow cooker, and honestly it beats most restaurant versions.
Jump To (scroll for more)
- ❤️ Why You'll Love This Recipe
- 🧅 Ingredients
- 👨🍳 Quick Overview: Crock Pot French Onion Soup
- ⏱️ How Long to Cook Onions in a Crock Pot
- ♨️ Troubleshooting Crock Pot Temperature
- 👨🍳 Options and Variations
- ↕️ Crock Pot Sizes & Adjusting Recipe
- 📋 Crock Pot Soup Recipes
- 🍽️ How to serve French onion soup
- ❄️ Storage & Reheating
- ❓FAQs
- 📖The Recipe Card
Featured Comment by Judith:
⭐⭐⭐⭐⭐
"Will definitely be making again! It tastes just like the French onion soup from our favorite restaurant!! Thanks for a great recipe!"
❤️ Why You'll Love This Recipe
- Better than most restaurants: Rich broth and deeply caramelized onions, topped with properly melted cheese - no salty shortcuts or soggy bread.
- Hands-off cooking: The slow cooker caramelizes the onions for you. No babysitting a soup pot all day.
- Simple ingredients: Onions, broth, bread, and cheese. Pantry staples turned into something elegant.
- Big, eloquent flavor on a budget: A soup that tastes refined but costs just a few dollars to make.
🧅 Ingredients
- Onions - Regular yellow or white onions work best for balance, but you can mix in sweet onions (Vidalia, Maui, Walla Walla) if you like a gentler flavor.
- Beef broth or stock - Go with a quality brand since it's the base of your soup. (I like Swanson®.)
- Butter - Salted or unsalted both work; just adjust the added salt if you use unsalted.
- Seasoning - Thyme (fresh or dried), salt, and black pepper. A little garlic is optional.
- Worcestershire sauce - Adds depth and savory "umami" flavor.
- Serving finish - Toasted crusty bread plus cheese (provolone, Gruyère, or Swiss are the classics) for the bubbly top.
👨🍳 Quick Overview: Crock Pot French Onion Soup
Chop onions into petals or rings and separate them.
Load the crock pot with onions, butter, thyme, salt, pepper, and Worcestershire. Cover and cook on high until onions are softened and deeply golden brown (about 9-10 hours, but go by color, not time).
✅ Pro Tip: Almost any slow cooker works, but older models and 2-quart minis can run hot or uneven-check early.
Add beef broth. In larger crock pots, add it all at once. In a 2-quart, add half after caramelizing the onions and the rest near the end.
Cook on high for at least 1 more hour to let the flavors combine.
Serving: Ladle hot soup into oven-safe bowls, top with toasted crusty bread, and cover with provolone, Gruyère, or Swiss cheese.
Broil until the cheese is bubbly and golden, 2-4 minutes.
👇 Scroll for the printable recipe card and complete photo instructions-or keep reading for tips, variations, and serving ideas.
⏱️ How Long to Cook Onions in a Crock Pot
The onions are ready when they're softened and deeply caramelized to a golden brown. That's the key - don't go by the clock alone.
- On high, most slow cookers will take about 9-10 hours.
- On low, plan for about 11-12 hours.
- Small 2-quart minis or older crock pots are often unpredictable since their thermostats can malfunction. To avoid burning, check the onions a couple of hours early and stir if needed.
Once the onions hit that deep golden stage, add the broth and let the soup cook at least one more hour so the flavors blend.
♨️ Troubleshooting Crock Pot Temperature
All slow cookers should eventually reach about 212°F on both low and high - the difference is how fast they get there.
But older crock pots or 2-quart minis are often unpredictable since their thermostats can malfunction. They may run too hot, too cool, or cycle unevenly.
That's why you always watch the onions, not the timer. You want them softened and deeply golden brown, not pale or burned. If your crock pot runs hotter than expected, check the onions a couple of hours early and stir if needed.
👨🍳 Options and Variations
- Onions - Yellow or white onions are classic. Mix in some sweet onions (Vidalia, Maui, Walla Walla) for a milder flavor.
- Seasoning - Thyme, salt, and black pepper are standard. Add a clove or two of garlic if you like.
- Butter - Salted or unsalted both work. If using unsalted, add a pinch more salt.
- Worcestershire sauce - Adds depth and savory umami. I use Lee & Perrins®.
- Cheese - Provolone, Gruyère, or Swiss are the traditional picks. Slices melt best, but shredded cheese works fine.
- Bread or croutons - Toasted slices of French bread are standard, but any crusty bread or oversized croutons will hold up under the cheese.
- Wine (optional) - Dry sherry, red wine, or dry white wine can be added with the broth. It isn't required in a crock pot version, but it does layer in more flavor.
↕️ Crock Pot Sizes & Adjusting Recipe
This recipe makes about 7 cups of soup (4 servings) and fits well in a 3-4 quart slow cooker.
- 2-quart mini crock pots: A full recipe fits, but it will be close to the top. After caramelizing the onions, add half the broth, then add the rest near the end so it cooks evenly without overflowing. Watch closely to prevent burning.
- Standard 3-4 quart: The best fit for the full recipe. Cook times will follow the guidelines as written.
- Full-size (5+ quarts): Works fine, but small volumes can cook faster. Check the onions early to prevent overcooking.
- Scaling the recipe:
- Half recipe - About 2 servings. Fits easily in a 2-quart mini.
- Full recipe - Best fit is 3-4 quarts. If using a 2-quart, add half the broth after caramelizing, then the rest near the end.
- Double batch - Needs 5 quarts or larger.
✅ Use the serving adjustment feature in the recipe card for exact ingredient amounts. Use the amounts in the ingredients list, not the instructions.
📋 Crock Pot Soup Recipes
Keep that slow cooker out and try more cozy soups:
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🍽️ How to serve French onion soup
Serve it as a main dish, appetizer, or side. The traditional way is in an oven-safe bowl (like a ramekin) with toasted bread and browned cheese on top.
If serving as the main dish, pair it with a fresh salad and good bread - Julia Child's French Bread, Peasant Bread, or Easy Dinner Rolls are all great choices.
❄️ Storage & Reheating
- Refrigerator: Store leftover soup (without the bread or cheese) in an airtight container for up to 4 days.
- Freezer: Freeze in meal-size portions for up to 3 months. Thaw overnight in the refrigerator before reheating.
- Reheating: Warm on the stovetop or in the microwave until hot. Then add toasted bread and cheese, and broil until the cheese is melted and bubbly.
❓FAQs
Yes. A full recipe will fit, but it's close to the top. After caramelizing the onions, add half the broth and the rest near the end so it cooks evenly without overflowing. A half recipe fits easily with no adjustments.
No. Wine is traditional when deglazing onions on the stovetop, but it isn't required in a crock pot version. If you'd like extra flavor, add a splash of dry sherry, white wine, or red wine with the broth.
Never cook with wine you don't like. If you do use wine (an option in the recipe card's tips), I suggest a non-sweet sherry, dry white, or red wine. A few suggestions: Sauvignon Blanc, Semillon, Pinot Grigio, Chardonnay, Merlot, or Pinot Noir.
The dish originated in France in the 18th century. Onions were cheap and plentiful, which made the soup a popular staple.
Caramelization is the slow browning of sugars in the onions. It is much more than merely browning - the goal is deeply caramelized onions that develop an intense nutty flavor and golden-brown color. That's what makes this soup special. Many stovetop methods require repeated rounds of cooking, but with this recipe the crock pot does the work for you.
📖The Recipe Card
Crock Pot French Onion Soup (Slow Cooker, Easy & Flavorful)
Video Slideshow
Ingredients
- 1½ pounds onions-white or yellow - about 3 medium size onions
- 1 teaspoon coarse salt
- 2 tablespoons butter
- ½ teaspoon pepper
- 1½ teaspoons Worcestershire sauce
- ½ teaspoon thyme
- 4 cups beef broth
- ¼ cup Wine - optional
- Crusty bread
- Provolone, Gruyère, or Swiss cheese
Step-by-Step Instructions
- Prep onions: Slice 1½ pounds of onions into petals or rings and separate into individual pieces (about 5-6 cups raw). Add to a 2-quart or larger crock pot.
- Season: Add 1 teaspoon of coarse salt, 2 tablespoons of butter, ½ teaspoon of black pepper, 1½ teaspoons of Worcestershire sauce, and ½ teaspoon of thyme. Stir to combine. (Butter may go in unmelted; stir it after 1 hour or melt first.)
- Caramelize: Cook on HIGH for 9-10 hours with the lid on until the onions are softened and deep golden brown. Go by color, not time. Then add 4 cups of beef broth-if using a 2-quart crock pot, add only 2 cups now.
- Simmer: Cook on high for at least 1 hour to allow the flavors to combine. If using a 2-quart, add the remaining 2 cups of broth about 15 minutes before the end.
- Toast & assemble: Toast crusty bread (brushed with butter) in the oven or a frying pan. Arrange ramekins or other oven-safe bowls on a sheet pan. Ladle hot soup into bowls and float the toasted bread on top.
- Cheese: Cover each bowl with provolone, Gruyère, or Swiss cheese.
- Broil until the cheese is bubbly and golden, 2-4 minutes.
Recipe Notes
Pro Tips
- Some slow cookers (mainly older crock pots and some smaller ones) run hot; watch for the endpoint-onions softened and deep golden brown-rather than the clock. (See troubleshooting in the post.)
- Using a much larger crock pot for this small recipe may cook a bit faster.
- Please check the onions halfway.
- Recipe scales well: As written, use a 2-4-quart crock pot. Double in a 5-quart or larger cooker; a half-batch works great too.
- Makes about 7 cups of soup (4 hearty servings).
- As written, use a 2-4-quart crock pot. For a double recipe, you will need a 5-quart or larger pot.
- Bread: a crusty French baguette or large croutons hold the cheese well. Cheese: we prefer provolone, but Gruyère or Swiss are classic.
- Quality matters here in the choice of broth. Do not settle for a generic.
- Wine (optional): Add ¼-½ cup (dry sherry, dry white, or red) with the broth.
- Storage: Refrigerate 3-4 days; freeze 3-4 months (without bread/cheese).
Your Own Private Notes
To adjust the recipe size:
You can adjust the number of servings above; however, only the amount in the ingredient list is adjusted, not the instructions.
Nutrition Estimate (may vary)
Editors Note: Originally published July 12, 2015. Updated with expanded options, refreshed photos, and a table of contents to help navigation.
Melanie Z says
This recipe seems so simple and easy. I always have seen recipes calling for red onion and we can't digest them, so this will be perfect to try very soon!
Thank you for sharing all your tips too. They are extremely helpful:)
Melanie
Mickey says
Instead of plain beef broth try using Campbells Beef Consume , it has some extra added flavor , plain beef broth just dosent it have , making your soup taste like you’re used to it tasting
Jan says
Do you use the same amount of the consume?
Mary Schaefer says
I have several French Onion Soup recipes, and this is by far the best. It is also the easiest. It will now be a regular in my winter rotation.
Thanks,
Mary
DonnieC says
I made this yesterday and it came out really well. I was quite surprised at the intensity of the flavour of the caramelised onions. I’m glad I chose to make this on a day when I was staying home as it is a slow cooker recipe that requires some attention.
My cooker does run hot so I heeded the advice and periodically peeked in to see how the onions were fairing towards the end of their nine hour cook time. I probably should have looked closer as there were a few heavily charred pieces at the end. I just picked them out prior to adding the beef broth.
I will make this again but will either make a point of giving the onions an occasional stir towards the end of their cooking time or turn down the heat for the last hour or so.
Dan Mikesell AKA DrDan says
Hi Donnie,
Welcome to the blog.
I do love this recipe but the variability in slow cookers can lead to some problems. About stirring, it is fine but may increase the cooking time some since it will take a while for the crock pot to get back up to temp.
Dan
Laurie says
Thank you Dr.Dan. This recipe is my winter go to. You’re right, quality ingredients are the key. Love the no fuss of the onions.
Dan Mikesell AKA DrDan says
Hi Laurie,
Welcome to the blog.
This is one of my favorites. Thanks for the note and rating.
Dan
Debby Stark says
What do I need to do with the broth to get it warm enough to keep it from cracking the crockpot?
Dan Mikesell AKA DrDan says
Hi Debby,
Welcome to the blog. If room temperature broth cracks your crock pot, it was a crock pot problem.
Frozen things like frozen chicken can crack a ceramic crock pot which is part of the reason for never putting frozen meat (or I guess frozen broth also) in a crock pot to cook.
Dan
Nancy says
Will the onions carmelize with the crock pot lid on? Can't wait to try this recipe and surprise my husband.
Dan Mikesell AKA DrDan says
Hi Nancy,
Lid on. I just add that to the recipe. The only crock pot recipe I have with (I think...) the lid off is the crock pot fudge.
Dan
Deborah Lein says
Dr Dan, what does te recipe mean by 'coarse salt'? Table salt? no-iodine table salt? Kosher salt? (I'm sure you don't mean road salt which looks nasty and is the coarsest I've ever seen. Deb L
Dan Mikesell AKA DrDan says
Hi Deborah,
I started using the term coarse salt a few years ago instead of typing out Kosher or sea salt all the time. So nothing special. If table salt is used, cut it back a little. And please always use iodized salt, I have seen enough goiters in my life.
Have a great holiday season.
Dan
Celesti says
Followed the recipe as written and the French Onion soup was a hit. I did use the yellow onions and the flavor was wonderful. The only change will be using my larger crock pot to cook down the onions. I used a smaller crock pot, and when I added the beef broth the liquid came to the top of the pot. My choice of cheese was Gruyère and the flavor complimented the dish. It was so good I had to share this site to several of my friends. Thank you for sharing a French Onion soup recipe that is easy to follow, make and serve.
Bllue says
I can hardly wait to try this recipe! It's a bit warm for it right now. I discovered your site on Facebook in the "Cooking For One or Two" page. I rarely look at that since I now use YOUR site!
I noticed a typo in step 4: "float toasted crusty bread on sou" - I think that should be "soup." :)
Dan Mikesell AKA DrDan says
Hi Bllue,
Welcome to the blog. Glad you are enjoying the blog and thanks for the proof read—fixed.
Enjoy the soup.
Dan
Judith says
Made this last night for supper. Will definitely be making again! It tastes just like the french onion soup from our favorite restaurant!! Thanks for a great recipe!
Judith says
Was I supposed to stir the onions, butter, etc. together before turning on the crockpot?
Dan Mikesell AKA DrDan says
Hi Judith,
Welcome to the blog.
Yes, stir together. I will add that to the text.
Dan
Anita says
My daughter gifted us with a 7 qt crock pot. It's just the two of us so I hate to double the recipe. What adjustments should I make? Just shorter time? Looks easy and we both love onion soup! Thanks
Dan Mikesell AKA DrDan says
Hi Anita,
Welcome to the blog.
Cooking in a bigger crock pot is generally just fine but because there is less mass in the cooker, it will cook a bit faster. You will see in the instructions about cooking to an nicely browned onions due to variability of crock pots. So cook to the endpoint not by time and check a few times early.
Hope that helps.
Dan
Kirsten says
I'm guessing since I doubled the recipe, I should also increase the cook time once the stock/broth is added. Your thoughts?
Dan Mikesell AKA DrDan says
Hi Kristen,
No, I would not increase that time, but an hour is the minimum, like all soups, a bit longer simmering is good. The biggest variable it the cooking time of the onions due to crock pot variables.
Dan