The best Crock Pot French Onion Soup has a rich beef broth and deeply caramelized onions. The easiest way to caramelize onions is by cooking them all day in a slow cooker rather than on the stovetop. The onion soup is served with toasted crusty bread and melted cheese.
🧅Ingredients
Onions
Beef broth
Butter
Seasoning—thyme, salt, pepper
Worcestershire sauce
Serving—cheese (gruyere, provolone, or Swiss) and crusty bread
Jump To (scroll for more)
- 🧅Ingredients
- 👨🍳How to Make French Onion Soup in a Crock Pot—Step-by-Step Photo Instructions
- 🤔When is French onion soup done?
- 👨🍳Make it right every time—options and variations
- ↕️Crock Pot sizes
- ↕️Changing recipe size
- 📋Crock pot soup recipes
- 🍽️How to serve French onion soup
- ❄️How to store and reheating leftovers
- ❓FAQs
- ♨️Toubleshooting crock pot temperature
- 📖The Recipe Card with Step-by-Step Instructions
Featured Comment by Judith:
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"Will definitely be making again! It tastes just like the French onion soup from our favorite restaurant!! Thanks for a great recipe!"
French onion soup is my favorite elegant comfort food; it is how I grade restaurants. Unfortunately, very few can match the deep flavor of this homemade onion soup recipe.
You can make the best French onion soup for pennies at home in almost any crock pot, from a 2-quart mini to a full-size crock pot. The caramelization takes time, so let the slow cooker do the work; you take the credit.
👨🍳How to Make French Onion Soup in a Crock Pot—Step-by-Step Photo Instructions
1. Chop onions into petals or rings. Separate the rings/petals into individual pieces.
2. Add all ingredients except the broth to a crock pot. Cover, and cook on high for 9-10 hrs. until "softened and deep golden brown." Do not cook by time.
3. Add 4 cups of beef broth unless you use a 2-quart crock pot; add 2 cups now and 2 cups near the end of cooking.
4. Cook on high for at least one hour to combine flavors.
🍽️Serving
5. Arrange ramekins or oven-safe bowls on a cookie sheet. Ladle hot soup into the bowls and add toasted crusty bread on top.
6. Cover each bowl with provolone, gruyere, or Swiss cheese
7. Broil until cheese is bubbly and golden, 2-4 minutes.
For more details, keep reading. See the Recipe Card below for complete instructions and to print.
🤔When is French onion soup done?
Watch for the endpoint of "softened and deep golden brown" for the onions being done. 9 to 10 hours on high is a reasonable estimate for most home cooks, but don't go by time alone. Crock pots vary a lot for long cooking on the high setting, so watch closely, especially if using an older or mini crock pot.
If you are unsure whether your slow cooker is reliable on high, it will take about 2 hours longer on the low setting.
👨🍳Make it right every time—options and variations
Quality ingredients are essential, but with so few ingredients, only use ingredients you trust. I like to use Lee and Perrins®️ Worcestershire Sauce and Swanson®️ beef broth or stock.
Onions—Regular yellow or white onions are the best choices, but some like adding red or sweeter onions like Vidalias, Mauis, and Walla Wallas.
Seasoning—The seasoning is limited to dry or fresh thyme, salt, and pepper. One to two cloves of garlic can be added to the onions. If you use unsalted butter, add a pinch more of salt.
Cheese—we like provolone, but some prefer gruyere or Swiss cheese. I like to use slices of cheese, but shredded cheese works fine.
Crusty bread or croutons: Toast buttered slices of French bread on a baking sheet in the oven or in a frying pan. Other crusty breads or large croutons may also be used to float the cheese. You can skip this step, but it is traditional and helps keep the cheese on top.
Optional—add dry sherry or dry red wine.
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↕️Crock Pot sizes
This recipe makes 7 cups of soup for 4 servings. It fits nicely in a small 3-4 quart slow cooker.
2-quart mini crock pot: Technically, you shouldn't use a 2-quart crock pot since it would be over 75% full and won't cook well. However, you can still use one by adding only half the broth until the last 15 minutes. One further warning about mini crock pots: they are notorious for poor temperature control, and you will run a high chance of the onions burning—watch closely.
Full-size crock pots (over 5 quarts): Small volumes in large crock pots tend to cook a bit faster. So, check early to see how your crock pot works with this recipe.
↕️Changing recipe size
A half-recipe fits easily in a 2-quart mini crock pot, while a double recipe needs a 5-quart or larger crock pot.
To change the recipe size, change the number of servings, and use the amounts in the ingredient list, not in the directions that do not adjust.
📋Crock pot soup recipes
Let's keep that crock pot out and try other great soup recipes. Start with Ham Bone Soup, then move on to Crock Pot Broccoli Cheese Soup or Crock Pot Cheeseburger Soup.
🍽️How to serve French onion soup
It can be served as a main dish, an appetizer, or a side dish. Traditional served in a small oven-safe soup bowl, like a ramekin, topped with browned cheese and supported by croutons or a slice of crusty bread.
Serve with Crock Pot French Dip Recipe for a wonderful comfort food meal. For an etiquette meal, serve it with Prime Rib Roast, Roasted Turkey Breast, or Oven Roasted Filet Mignon.
Grilled Filet Mignon
Learn How to Grill Filet Mignon to perfection in about 10 minutes. With these simple step-by-step photo instructions, you can easily cook the best-grilled filet mignon.
If served as the main dish, it should be accompanied by a fresh salad and good bread, such as Julia Child's French Bread or Easy Dinner Rolls.
❄️How to store and reheating leftovers
Leftover soup (without the bread or cheese) should be sealed airtight and refrigerated for 4 days or frozen for 3 months.
Frozen French onion soup should be thawed overnight in the refrigerator before reheating. It can be reheated on the stovetop or in the microwave. Then, add toasted crusty bread and cheese before browning under the broiler.
❓FAQs
Wine is not required for onion soup. It has traditionally been used to deglaze the pan after caramelizing the onions—not needed with a crock pot. However, wine also added flavor to the soup.
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: Sauv Blanc, Semillon, Pinot Grigio, Chardonnay, Merlot or Pinot Noir.
French Onion Soup is from France in the 18th century; this traditional French soup can be used as an appetizer or a main course. Part of the reason for the initial popularity was that onions were cheap and readily available.
Caramelization is the browning of sugar through the oxidation of sugars. When correctly done, it results in a deep, nutty flavor and brown color—just what we need for a great soup.
Many techniques for caramelizing onions require multiple rounds of caramelization on the stovetop, which will keep you working all day at the stove. But you can do it much easier in a crock pot with this recipe.
♨️Toubleshooting crock pot temperature
On all crock pots (slow cookers), the maximum temperature on both low and high should be in the 212° range, but it will take different times to get there. That is all controlled by a thermostat that has improved over the years but can still malfunction.
If you use a full-size crock pot for this smaller recipe, you have less material to heat, and it may cook faster. Mini-crock pots are known for temperature control issues.
If you question your crock pot or use a very small, large, or older one, please watch the endpoint when caramelizing onions—you want deep golden brown.
📖The Recipe Card with Step-by-Step Instructions
Crock Pot French Onion Soup
Video Slideshow
Ingredients
- 1 ½ pounds onions—white or yellow - about 3 medium size onions
- 1 teaspoon coarse salt
- 2 tablespoons butter
- ½ teaspoon pepper
- 1 ½ teaspoon Worcestershire sauce
- ½ teaspoon thyme
- 4 cups beef broth
- ¼ cup Wine - optional
Finishing then serving
- Crusty bread
- provolone, gruyere, or Swiss cheese
Step-by-Step Instructions
- This recipe fits in a 2-quart mini crock pot and works well in a 3-4 quart crock pot. A bigger crock pot may cook faster, so pay attention to color.
- Chop 1 ½ pounds of onions into petals or slices and separate them into individual pieces, about 3 medium-sized onions. Add them to a 2-quart or larger crock pot. If you are doubling the recipe, 5 quarts or a larger crock pot are needed.
- Add 1 teaspoon of coarse salt, 2 tablespoons of butter, ½ teaspoon of black pepper, 1 ½ teaspoons Worcestershire sauce, and ½ teaspoon of thyme. Then, stir them together. The butter can go in unmelted, but you must stir in 1 hour or melt it in the microwave beforehand.
- Cook on high for 9-10 hours with the lid on until it is nicely darker brown. Be warned that some crock pots may run hot. Please watch for the endpoint of "softened and deep golden brown" for the onions being done, and don't go by time alone. Then add 4 cups of beef broth except if using a 2-quart crock pot, only add 2 cups.
- Cook on high for at least one hour to combine flavors. If using a 2-quart crock pot, add the final 2 cups of broth about 15 minutes before ending.
- Toast crusty bread brushed with butter in the oven or a frying pan. Preheat the broiler to high. Arrange ramekin or oven-safe bowls on a cookie sheet. Ladle hot soup into the bowls and float toasted crusty bread on the soup.
- Cover each bowl with provolone, gruyere, or Swiss cheese
- Broil until cheese is bubbly and golden, 2-4 minutes.
Recipe Notes
Pro Tips
- Be advised that some crock pots may run hotter, so watch for softened and deep golden brown as the endpoint for the onions being done. If your crock pot boils on low, it may be in the "runs hot" category, so use low for 10-12 hrs—more discussion in the post.
- Also, using a much larger crock pot for this small recipe may cook a bit faster.
- Please check the onions halfway through due to the above.
- This recipe can be easily doubled but could also be cut in half.
- This makes about 7 cups of soup. I call that four servings.
- As written, use a 2 to 4-quart crock pot. For a double recipe, you will need a 5-quart or larger pot.
- Some crusty bread or large croutons are used to float cheese on top. You can use what you want, but I chose a nice crusty French baguette. For the cheese, we like provolone, but some prefer Gruyere or Swiss.
- Quality matters here in the choice of broth. Do not cheap out on generic.
- Wine can be added to the soup with the broth. A ¼-½ cup would be about the right amount.
- Good refrigerated for 3-4 days and 3-4 months frozen.
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.
Liz Kelly says
So good and easy to make.
I used an organic, gluten free, low sodium off the bone beef broth. Highly recommend, the flavor is perfect.
Nushka says
This is one of my favourite recipes from the blog. Easy to make and so delicious.
Katie says
Hi. My husband and I love this soup recipe. It's my go to base for making Beef French Dip.
However, in reading the instructions, you might want to make an edit in either step 1 or 2 on the crockpot.
Thanks for a keeper recipe!
Dan Mikesell AKA DrDan says
Hi Katie,
Welcome to the blog and thanks for the proofread. It didn't need the repeat about the crock pot size.
Hope you enjoy the soup.
Thanks for the note and rating.
Dan
Patti says
What is your feelings about beef stock as opposed to beef broth? I’ve found that in the case of chicken stock, it’s not only tastier, but the sodium content is so much lower (50 mg), that it’s good for heart healthy diets. You have to add salt to bring out the flavor of whatever you are making, but it’s in your control, and you aren’t starting with 450 to 700 mg. (estimates based on what I’ve seen) to start with. Even low sodium broths aren’t great. I haven’t looked for beef stock specifically, I usually use chicken stock, but I love French Onion Soup, so either way, it’s going in my tummy!
Dan Mikesell AKA DrDan says
Hi Patti,
Welcome to the blog.
Like many things, it depends on usage. In chicken broth vs stock, I can tell a minimal difference. But in beef, I personally can not detect a difference in what I use in taste. Years ago, beef broth was bad but is much better in recent years.
Regarding sodium, you can get stock/broth with anywhere from zero to full sodium. So it is a matter of personal choices and any health concerns. If you have no medical issues, the normal sodium ones are generally fine. If you have a medical issue, the amount of sodium restriction you should have should be determined by you and your doctor.
For my taste, I'm usually happy with some decrease in sodium.
For this recipe, you should use beef since that is a huge part of the taste and the Worcestershire sauce help boost that but is also relatively high in sodium but the low sodium version not quite as good. Years ago, when the beef products were so poor, we would use vegetable broth and more Worcestershire sauce.
Thanks for the note.
Dan
Olivia says
I made this yesterday. However, I got impatient after about 6 hours in the crockpot and I'm glad I did! The onions were about to burn! I think it's really important to check the onions in the middle incase your crockpot cooks quickly. After the 6 hours, I skipped to the instructions to add the broth and cook another hour and it turned out wonderfully! Thanks!
DrDan says
Hi Olivia,
Welcome to the blog.
Glad you checked it. Crock pots are so variable.
Cooks Illustrate suggest 12 hours on high. I think my 9-10 hr is good for the vast majority of crock pots. I did just add another warning about crock pot variabilities and suggested a fast peak at 6 hours since most people don't know their crock pots well.
Thanks for the note and the rating.
Dan
karin says
Best French onion soup I ever had! Definitely making again!!
DrDan says
Hi Karin,
Welcome to the blog.
I many times judge a restaurant on their onion soup. Most fail. I think this one passes.
Thanks for the note and rating.
Dan
Angie says
Wow! This soup was so amazingly delicious and easy. I think we just found our new New Year's tradition -this easy yet fabulous soup!!!! The family absolutely loved it!
DrDan says
Hi Angie,
Welcome to the blog.
I do love French onion soup and this is so simple.
Thanks for the note.
Dan
Thomas says
This was absolutely delicious! I personally needed it to be ready for a late lunch the next day. So I added my onions and unmelted butter, cooked on high for about hour and half; mixed my butter then dropped it to low for the remaining 16 hours. I had just a couple darker onions not quite burnt, otherwise almost all the onions were perfectly carmalized! I added my broth for two hours on low rather then the hour high. And it turned out perfect!
DrDan says
Hi Thomas,
Welcome to the blog.
Thanks for the description of your technique. Hopeful others will find it useful. I think as long as you get a good caramelization on the onions it will do well.
Thanks for the note and Happy New Years.
Dan
Sarah Newman says
Absolutely wonderful soup. Mine took between 7-8 hours to be ready in the slow cooker. Definitely a new favorite in my house. Thank you!
Kristine says
Just made this and OMG it tastes sooo good! I only have a large crockpot, so I started watching the onions around 7 hours. I only had one can of beef broth but had a packet of Au Jus (followed the directions) and added it. Wow, the flavors of the onions combined with the beef stock are friggin amazing. I'm skipping bread for a bit, so I just added some mozz cheese. I live on Maui, so the weather really never gets chilly, but this hearty soup brings back so many nice memories of living in colder weather (many years ago). Thanks so much!
Donna J G says
Can I choose to make on stove top?
DrDan says
Hi Donna,
Yes but no. This recipe is a derivative of several stovetop and crockpot recipes. The stovetop recipes all seemed to require lots of babysitting all day long. So much work. If you just do a fast stovetop caramelization of the onions, your soup will be lacking. So yes you can but I suggest using an actual stovetop recipe
Dan
DONNA SEAGO says
I made this yesterday............I doubled the recipe...................everyone loved it.............couldn't have been easier.........
DrDan says
Hi Donna,
I have done this one over and over.
Thanks for the note.
Dan
Vince Juliano says
Hi Dr Dan,
This looks like a Godsend for an oldie moldie newly single guy. I'll keep you posted on my successes......and failures.
Thank you so much.
cory says
I was flipping through a bunch of recipes on google because the original video and recipe i was referring to were very different cooking instructions from eachother!?
So i basically just decided to wing it. Then i found this recipe and its like exactly what i concocted! Put my heart at ease knowing its going to still be great.
DrDan says
Hi Cory,
Welcome to the site. Somewhat like you, I see a recipe I'm interested in but then research the heck out of it the simplify,
Dan
joan says
Recently made this. Turned out great. So much easier than slowly cooking onions on the stove. 9 hours on high was good. Will be making onion soup a lot more now.
DrDan says
Hi Joan and Happy Holidays
This does turn out a great soup. Once you know your crock pot, this is a put it on in the morning and have a great dinner type recipe.
Thanks for the note.
Dan
Melanye says
Does the cook time change if using a larger crock pot?
DrDan says
General rules are that too small may prolong cooking time if more than 75% full. Too big is usually considered fine. BUT here we are prolonged cooking on high. I would expect it to cook faster. And if you have one of those pots that boils on low (IE a hot pot) we could be burning the onions. If in doubt, cook on low and look for the end point of soft and deep golden brown.
Dan