Monday, October 21, 2019

Slow Cooker French Onion Soup (With Video)

Slow Cooker French Onion Soup is ridiculously easy to make. It is incredibly flavorful and you can top it with as much cheese as you want!
Slow Cooker French Onion Soup is one of the easiest recipes you can make in your slow cooker. This soup is also very budget friendly, unless you decide to spend all your dollars on the most expensive cheese, and that will be totally worth it, because cheese equals happiness.

But guys, if you ever wanted to try to make French Onion Soup, this slow cooker version is fool-proof and also makes the most amazing and flavorful soup you will ever taste!

Hey guys, it's Catalina from Sweet and Savory Meals here. I am happy to be a contributor on TSRI and add recipes to Donna and Chad's already great collection.

A few weeks ago I introduced you to this amazing Slow Cooker Baked Potato Soup, that now has more than 10M views on Facebook!

Since we are in full-force soup season (aka cold winter) I wanted to share with you another soul warming soup recipe. I hope you enjoy this Slow Cooker French Onion Soup and if you are looking for more delicious soups, check this Slow Cooker Chicken Tortilla Soup!

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  • You can technically use other variations of “white” onions, but sweet onions work best in this recipe. Also, please do NOT use red onions.
  • This recipe takes a long time to make, not actively, but the slow cooker will be on for half a day. I recommend starting early morning to cook the onions. Considering that you will have to stir them halfway.
  • If you want to cut down the cooking time, you can brown the onions on the stove, until perfectly brown and caramelized. You will have to do this on low heat, not to burn the onions, for about 1 ½ to 2 hours. You will have to add a little liquid if needed. When transferring the onions to the slow cooker, transfer the juice from the onions as well. 
  • The thyme and bay leaves are optional, they add great flavor, but if you don’t have any on hand, you can skip these.
  • When it comes to adding the sugar, I used 2 teaspoons only and also, preferably use brown sugar as it adds that caramel flavor when combined with the onions. You can add more sugar, if you prefer the soup sweeter.
  • I like to add the sherry vinegar and Worcestershire sauce to the onions, for a deeper flavor. You can also add these when you add the beef stock.
  • You can also use asiago cheese, or a mix of Gruyere and asiago.


  • Slow Cooker - the slow cooker is almost my most used kitchen gadget, especially during fall/winter! It's just so convenient, and lets face it, it makes comfort food taste even better!
  • Worcestershire Sauce  - enhances the beef flavor in recipes that use beef, or in this case beef stock.


With love from our simple kitchen to yours. 

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See how easy this Slow Cooker French Onion Soup  is to make. Watch the video!!!

Yield: 8

Slow Cooker French Onion Soup

Slow Cooker French Onion Soup is ridiculously easy to make. It is incredibly flavorful and you can top it with as much cheese as you want!
prep time: 15 minscook time: 16 hourtotal time: 16 hours and 15 mins


  • 3 pounds sweet onions, thinly sliced
  • 4 tablespoons unsalted butter, melted
  • 2 teaspoons brown sugar
  • 2 teaspoons sherry vinegar
  • 1 tablespoon Worcestershire sauce
  • 5 fresh thyme sprigs
  • 3 bay leaves
  • 6 cups beef stock
  • Kosher salt and freshly ground black pepper, to taste
  • 1 (12-ounce) French baguette, sliced
  • 2 cups Gruyère cheese, shredded


  1. Add the thinly sliced onions to a 6-qt slow cooker. Stir in butter, brown sugar, 1 teaspoon salt, sherry vinegar and Worcestershire sauce.
  2. Cover and cook on high heat for 8-9 hours or on low for about 12-14; or until onions are caramelized and browned. Make sure to stir halfway, as needed, to prevent burning.
  3. Stir in beef stock, season with salt and pepper, to taste and add thyme sprigs and bay leaves. Cover and cook on high heat for 2-3 hours or on low for 4-5 hours. When ready discard thyme and bay leaves.
  4. Preheat oven to broil.
  5. Place baguette slices onto a baking sheet and broil until golden brown on both sides, about 1-2 minutes per side.
  6. Divide soup into ovenproof bowls, place the bowls on a baking sheet. Top with toasted baguette slices, about two slices per bowl, the bread should cover the soup; top with lots of shredded cheese.
  7. Place into the oven and broil until the cheese is bubbly and golden brown, about 2 minutes.
  8. Serve immediately.

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  1. Cannot get to "print" for the onion soup. Every time I click the 'print' option, it goes to a different soup (potato). Very confused.

    1. Holli@TheSlowRoastedItalianJanuary 17, 2018 at 8:41 AM

      Thanks Patte, it is fixed now, Enjoy!

    2. I looked for that print button on the recipe and didn't find it, so I highlighted just the title to the end of instructions, right clicked on the highlighted text and clicked print. and it printed picture and all.

  2. Hi! I can't find Sherry Vinegar near me can you sub sherry wine? or can you think of something else that would work? Thanks!

    1. We used sherry wine today and loved the soup.

    2. Thank you! Trying it tomorrow. Everyone is looking forward to it!

    3. I'm in the middle of making this recipe right now! My house smells Heavenly!!!!

    4. your actually supposed to add a dry white wine, I wouldn't skimp on this , its cooking for hours so the alcohol, if your worried about it , will cook off

  3. Where are those soup crocks fron!?

    1. I recently found some at Bed bath and beyond


    1. The Sherry Vinegar has no alcohol. Don’t use Sherry Wine.

    2. the alcohol cooks off in the hours in the slow cooker

  5. Replies
    1. Never saw a reply to the question of if this can be frozen.

  6. I labored a long time making this only to discover I used too much brown sugar, I ruined it. It was my fault totally, I misread and thought it said two tablespoons of brown sugar. I'm going to try it again though. Don't make my mistake please~!~

    1. I would think if you used sweet onions, you may not need sugar

  7. I like thos post, enjoyed this onee thank you for
    putting up.

  8. How much does it make? I couldn't find that anywhere. Thanks!

    1. It says on the top of the recipe that it yields:8 so it is for 8 persons

  9. Replies
    1. I used Vidalia onions and it worked great


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