French onion soup feels fancy, but it doesn’t need to be hard. This Crockpot French Onion Soup delivers deeply caramelized onions, rich beef broth, and melted cheese over toasted bread—all with almost no work.
The slow cooker does the onion work for you—no babysitting a soup pot. It works in any size crockpot, from a 2-quart mini to a full-size slow cooker, and honestly it beats most restaurant versions.
⏰ Quick Answer: How Long to Cook French Onion Soup in a Crockpot
Cook about 9–10 hours on high until the onions are soft and deeply caramelized. Add broth and cook 1 more hour to blend the flavors.
(For low setting, plan 11–12 hours total.)
Jump To (scroll for more)
- ❤️ Why You’ll Love This Recipe
- 🧅 Ingredients
- 👨🍳 Quick Overview: Crockpot French Onion Soup
- ⏱️ How Long to Cook Onions in a Crockpot
- ♨️ Troubleshooting Crock Pot Temperature
- 👨🍳 Options and Variations
- ↕️ Crockpot Sizes & Adjusting Recipe
- 📋 Crockpot 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: Crockpot French Onion Soup
Step-by-step overview for making French Onion Soup in your crockpot—simple and foolproof.
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 Crockpot
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.
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♨️ 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 slow cooker version, but it does layer in more flavor.
↕️ Crockpot 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 crockpots: 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 crockpot.
- 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.
📋 Crockpot Soup Recipes
Keep that slow cooker out and try more cozy soups:
🍽️ 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, you can make French Onion Soup in a 2-quart mini crockpot. The full recipe will fit, but it’s close to the top. After the onions are caramelized, add half the broth first 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
Crockpot French Onion Soup (Slow Cooker, Easy & Deep Flavor)
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.
Lisa Huff says
Oh wow, this looks so good!
Mary says
I've had mine cooking for 2 hrs so far and my house smells Ah-MAZING! Can't wait for dinner tonight.
Mary says
It didn’t disappoint! No burnt onions even cooking on high for 9 hrs. Perfectly carmalized and a fantastic soup!
Emily says
I made this recently and it was SO easy and delish! I ended up buying jarelsburg cheese. I will make this again for sure!
DrDan says
Thanks for the note. It is one of my favorite soups.
Dan
Chris says
At what point to you add the ingredients from 2nd crock pot? 😊
DrDan says
No second crock pot. Carmalize onions then add broth and cook some more. Then is ready to put into bowls with bread and cheese.
Dan
Colette Watts says
Before I make this can you freeze the soup.
Tks
DrDan says
Yep
Cera says
Cut a huge portion of time off by quickly caramelizing your onions in butter prior to adding to the crock pot. Adds a ton more flavor and onions are not mush.
Paige says
What kind of cheese and bread do you prefer to use? And how much of each?
DrDan says
I like a crusty French or Italian bread with Provolone cheese. About 1/2 to 3/4 inch thick slice of the bread to cover the dish and just enough cheese to cover also.
Jennifer says
Should I use yellow onions??
DrDan says
Yellow or white.
Nicole says
So I'm like Dan, mine burned a lil. I started it at 730am, it is now 111pm can i add the broth and let it sit on low all day? The onions are pretty camerlized but my husband and son don't get home till about 5pm
DrDan says
I think some crock pots run too hot for this recipe on high. With your pot, do low next time. Remove from heat now since they are caramelized and refrigerate. Then about an hour and a half before you need it, add the broth and cook on low. It does need to simmer some with the broth and not just reheat.
Willie Mitchell says
Sound delious.. Only thing I dislike onions ?
Dr. Horshenschwartz (from the clinic) says
Excellent. Made it a couple months ago, making it again today with 6 pounds of onions. Smells amazing!
Dan says
You must have a typo. When you cook onions on high for 9 hours you get burnt onions. I know because I did it. I'm mad that I didn't use my own common sense. You should change that to say LOW for 9 hours. Please fix this so others like me dont have their whole house smelling of burnt onions.
DrDan says
Hi Dan...
Sorry it didn't work well for you but high is correct. I did it twice and 9 hours on high worked great in two different pot I have. I check some references before I replied and they are all over the place. 8 hours on low to 14 hours on high. Cooks Country does high for 10-12 hours...
So what went wrong. 1) your crock pot runs hot and/or 2) some variation in the onions.
I'm putting an advisory on the recipe stating to cook to "softened and deep golden brown". You want the caramelization.
Thanks for the note
DrDan
Paula Mencucci says
I had the same problem. Burnt onions....I'm sad because I use the crockpot when I"m not home to cook and when I come home after a long day to ruined dinner, I'm extremely disappointed :( Apparently my crockpot runs hot, but only on one side...
DrDan says
Hi Paula,
I changed some wording about hot pots. I believe it was Crock Pot brand that had the heating element located in one location near the front if I remember right and not around the pot. They had a lot of localized burning from what I understood.
The warning I added about hot pots was if you see boiling when cooking on low, then you should assume a hot pot. On low a crock pot should be 207 or less. Most run right at 200. It is harder to measure the temperature on high since it should be about 250 but some pots run 300. Since both are above the boiling point you can't get an accurate measurement without special equipment. That, of course, does not address hot localized spots.
Again, sorry you had an issue.
Dan
Kathy Heiber says
This is delicious....I have always loved French Onion Soup and now I can have it whenever I want....YAY!!!
rating...+10
Peg says
Do you leave it covered or open?
DrDan says
Covered.
Steven House says
I LOVE french onion soup, but rarely make it since caramelizing the onions is almost a day long affair. For some reason I never considered using my crock pot. I can't wait to try this. Many thanks!
Cheryl S. says
LOVE the onion soup. Even my very picky 10 year old gave it a definite thumbs up! Who knew it could be so easy?!?
DrDan says
Thanks for the note and rating. I have repeated this several times.