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
- 📖 Recipe
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!"
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.
↕️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.
📖 Recipe
Crock Pot French Onion Soup
Video Slideshow
Save this recipe to your inbox for later!
Get the recipe link via email to comeback later.
You may recieve the email without subscribing if you wish, but the subscription is convienent and has an easy one-ckick unsubscribe.
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
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 may adjust the number of servings in this recipe card under servings. This does the math for the ingredients for you. BUT it does NOT adjust the text of the instructions. So you need to do that yourself.
Nutrition Estimate
© 101 Cooking for Two, LLC. All content and photographs are copyright protected by us or our vendors. While we appreciate your sharing our recipes, please realize copying, pasting, or duplicating full recipes to any social media, website, or electronic/printed media is strictly prohibited and a violation of our copyrights.
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.