• Skip to primary navigation
  • Skip to main content
  • Skip to primary sidebar
  • Skip to footer

Simply So Good

  • Home
  • About
  • Recipes
  • Contact
You are here: Home / Recipes / Soups / Slow Cooker French Onion Soup

Slow Cooker French Onion Soup

October 22, 2021 Updated December 14, 2024 17 Comments

40 shares
  • Share
  • Tweet
Jump to Recipe Print Recipe
overhead shot of french onion soup with thyme sprigs on top of gruyere toast

Slow Cooker French Onion Soup is everything you dream of in a French onion soup.  The slow cooker will slowly caramelize the onions to perfection.  Just add broth and fresh herbs and continue to slow cook.  The onions will melt in your mouth and of course, topped with baguette and oozy French Gruyere cheese.

overhead shot of french onion soup with thyme sprigs on top of gruyere toast

French Onion Soup is one of my favorite warming soups for fall and winter.  Using a slow cooker creates the perfect caramelized onions along with a deep, flavorful broth.  The toasted baguette will soak up the rich broth topped with bubbling gruyere.  

 

Caramelizing the Onions

Sliced onions on a board with garlic, knife, and coconut sugar on the side

Slicing the onions will be the most difficult part of this recipe.  It’s not hard, but you will probably shed a tear or two.  Using a mandolin will make the slicing a breeze.  I like to use sweet Walla Walla onions.  You can use whatever sweet onion you can find.  Slice 3-4 large onions.  

Several sliced onions, butter, onion, garlic, measuring spoons

You will, also, need 1/2 cup of unsalted butter, 3 large cloves of garlic, 2 tablespoons coconut sugar, or brown sugar (this will help brown the onions nicely you can omit the sugar altogether if you wish).  Lastly just 1/2 teaspoon salt.  The broth used will add more salt to the soup.  It’s best to under salt because you can always add more to your liking.  Once the salt is in the soup, it can not be removed!  

Slow Cooker French Onion Soup

Butter chunks in crock pot insert for french onion soup1
French onion soup in a Crockpot filled with sliced onons2
French onion soup in a Crockpot with onion slices sprinkled with coconut sugar and salt3
For french onion soup Sliced onions in a crockpot with a garlic press adding garlic4
For french onion soup Onions cooked down with broth5
  1. In the bowl of a crockpot melt butter. 
  2. Add sliced onions.
  3. Sprinkle with the coconut sugar, 1/2 tsp. salt.  Stir to coat onions. 
  4. Add chopped garlic to the top of the onions.   Cook on low for 6 hours. Stirring every 30 minutes or so.  
  5. The onions will be reduced significantly in size and will be more golden in color.  Now that the onions are the perfect golden color, add the chicken and beef broth, 3-4 sprigs of fresh thyme, and a large bay leaf. Continue to cook for an additional 8 hours.  

In the meantime:

  • Slice the baguette into 1-inch slices.  Butter both sides of the bread and place on a hot griddle or skillet.  Toast both sides.  
  • Grate the gruyere cheese and set it aside.

The Finishing Touches

Thyme removed from crockpot
Adding fresh thyme and parsley to french onion soup
  • After the soup has cooked for 8 hours, remove the thyme springs and bay leaves.  Discard.
  • Add in fresh chopped thyme and parsley.  

Serving French Onion Soup

Ladle the hot soup into individual crocks, bowls, or mugs.  Top with enough of the toasted baguette to cover the top.  Load on the shredded gruyere and place under a hot broiler and cook until the cheese is melted and beginning to bubble.  Enjoy the warmth of this classic French Soup.

Just check out this oozy gooey cheese stretch.  Best! ❤️

overhead shot of french onion soup with thyme sprigs on top of gruyere toast
5 from 25 votes
Print

Slow Cooker French Onion Soup

This Slow Cooker French Onion Soup recipe is everything you dream of in a French onion soup.  The crockpot will slowly caramelize the onions to perfection, with no need to cook on the stovetop first.  Just add broth and fresh herbs and continue to slow cook.  Top bowls with crispy baguette and oozy French Gruyere cheese for an elegant but effortless meal!

Course Appetizer, Dinner, Soup
Cuisine American, French
Keyword crock pot french onion soup, Crockpot French Onion Soup, French Onion Soup, Onion Soup, Slow Cooker French Onion Soup
Prep Time 15 minutes
Cook Time 12 hours
Total Time 12 hours 15 minutes
Servings 8 Servings
Calories 366 kcal
Author Janet Barton

Ingredients

  • 3-4 large sweet onions organic, cut in half and sliced 1/8-1/4 inch thick
  • 1/2 cup unsalted butter
  • 1-2 tablespoons coconut sugar depending how sweet onions are
  • 1/2 teaspoon salt
  • 3 cloves garlic minced
  • 4 cups chicken bone broth
  • 4 cups beef bone broth
  • 1-2 tablespoons Worcestershire sauce
  • fresh thyme
  • 1 bay leaf
  • salt
  • fresh ground white pepper
  • fresh parsley
  • 1 loaf French Baguette Slice into 1-inch thick slices
  • 2-3 cups Gruyere cheese Shredded

Instructions

  1. In the bowl of a crockpot melt butter. Add sliced onions, coconut sugar, 1/2 tsp. salt. Stir to coat onions. Add minced garlic to the top of the onions.

  2. Cook on low for 4-5 hours. Stirring every 30 minutes or so.

  3. Add broths, about 4 sprigs of fresh thyme and 1 bay leaf.

  4. Cover and continue to cook on low for an additional 8 hours.
  5. Before serving add Worcestershire sauce to taste. Season with salt and white pepper and additional fresh herbs.
  6. Slice baguette into 1-inch slices. Butter both sides and place on a hot griddle or skillet until golden brown.

  7. Pour steaming hot soup into serving bowls. Top with 1-2 slices of baguette (enough to cover the top of the soup). Divide shredded gruyere cheese over the top of the baguette. Place under a broiler until cheese begins to bubble and is completely melted. Serve.

Recipe Notes

  • Soup can cook for as long as 12 hours on low. 
  • Can use 8 cups vegetable stock in place of Chicken and Beef broth.  
  • I like to cook the onions during the day, then add the broth and cook through the night.
  • Soup can be cooled and refrigerated for 3-4 days. Reheat when ready to serve.
  • This recipe can serve up to 8 depending on the size of bowls and amounts used per serving.
Nutrition Facts
Slow Cooker French Onion Soup
Amount Per Serving
Calories 366 Calories from Fat 216
% Daily Value*
Fat 24g37%
Saturated Fat 14g70%
Trans Fat 1g
Polyunsaturated Fat 2g
Monounsaturated Fat 7g
Cholesterol 67mg22%
Sodium 553mg23%
Potassium 188mg5%
Carbohydrates 19g6%
Fiber 1g4%
Sugar 2g2%
Protein 19g38%
Vitamin A 670IU13%
Vitamin C 1mg1%
Calcium 371mg37%
Iron 1mg6%
* Percent Daily Values are based on a 2000 calorie diet.

You May Also Love

Pumpkin Apple soup in a bowl
Slices of No-knead Partially sliced Green Chile Cheddar Bread
crockpot burrata French onion soup
baked no-knead pumpkin harvest bread with a cinnamon stem in the middle. white and orange mini pumpkins in background

Share this:

  • Click to share on X (Opens in new window) X
  • Click to share on Facebook (Opens in new window) Facebook

Related

Filed Under: Soups, Vegetarian

Previous Post: « Slab Apple Pie
Next Post: Giant Cheddar Twists »

Reader Interactions

Comments

  1. tann says

    February 9, 2024 at 2:56 am

    I didnt know i was a French Onion Soup fan, until now… just, wow!

    Reply
    • Janet Barton says

      February 9, 2024 at 3:44 am

      Wow! Thank YOU!

      Reply
  2. Chrissa says

    February 8, 2024 at 9:21 pm

    5 stars
    OMG! This is SUCH a good soup! Super delicious!

    Reply
    • Janet Barton says

      February 9, 2024 at 12:10 am

      Thank you so much. I’m so glad you like it!

      Reply
  3. Matt says

    February 8, 2024 at 8:09 pm

    5 stars
    I wouldgive this 4 1/2 stars if possible but i cant. Nothing is 5 star worthy…nothing. Good soup

    Reply
    • Janet Barton says

      February 9, 2024 at 12:11 am

      Thanks Matt. I’ve had some food that ranks 5 stars! You need to get out more.

      Reply
      • T says

        February 9, 2024 at 2:52 am

        5 stars
        Haha i love this so much, and i agree, this soup definitely deserves 5 stars!

        Reply
        • Janet Barton says

          February 9, 2024 at 3:44 am

          Thank you! It’s so warming during the cold winter season.

          Reply
  4. Ryan says

    February 8, 2024 at 7:07 pm

    5 stars
    I used your suggestion of using vegetable broth to make it vegetarian friendly for my family and it turned out so great! Thank you for the recipe

    Reply
    • Janet Barton says

      February 9, 2024 at 12:11 am

      Thanks Ryan. You’re the best! I love using veggie broth myself.

      Reply
  5. billy dykhouse says

    February 8, 2024 at 7:03 pm

    5 stars
    This is my favorite version of my favorite soup! I keep coming back to this recipe

    Reply
    • Janet Barton says

      February 9, 2024 at 12:12 am

      Thanks Billy. I can always count on you!

      Reply
  6. Tiff says

    February 8, 2024 at 7:02 pm

    5 stars
    Easiest, Yummiest French onion soup recipe out there! The slow cooker makes it so easy to make, all you have to do is chop, toss it in the pressure cooker, and walk away! It is my new favorite autumn soup!

    Reply
    • Janet Barton says

      February 9, 2024 at 12:13 am

      Thank you so much, Tiffany. This soup is so warming.

      Reply
  7. Spence says

    February 8, 2024 at 6:55 pm

    5 stars
    Simply so good should Rename their site to simply so damn good. This soup is amazing!

    Reply
    • Janet Barton says

      February 9, 2024 at 12:14 am

      Ha Ha…right?! Thank you so much.

      Reply
    • T says

      February 9, 2024 at 2:52 am

      5 stars
      I second this suggestion!

      Reply
5 from 25 votes (17 ratings without comment)

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Recipe Rating




This site uses Akismet to reduce spam. Learn how your comment data is processed.

Primary Sidebar

About Me

Janet Barton

Hi I'm Janet and this is where I share my delicious made-from-scratch seasonal recipes that I make at home for my family every day.

I believe cooking from scratch, using unprocessed and whole foods is an important part of healthy eating. My goal is to help you create amazing recipes by providing easy step-by-step photos and instructions.

Read More »

Trending Recipes

  • No-knead Crusty Bread in a Dutch oven No-knead Crusty Bread

  • Lemonade and raspberry lemonade in tall glasses Old Fashioned Lemonade

  • pan of frozen lemon curd ice cream with ice cream scoop No-Churn Lemon Curd Ice Cream

  • Lemon Curd Ice Cream in bread pan with spoon Lemon Curd Ice Cream

  • Large jar of spicy sweet bread and butter pickles with habanero peppers and onions. Spicy Sweet Refrigerator Pickles

  • Wooden board with chocolate cookies with half chocolate icing and half vanilla icing Chocolate Half Moon Cookies

  • Blackberry Raspberry Jam

  • Several chocolate drop cookies on white background Chocolate Drop Cookies

  • Jerk Spatchcock Chicken on wood Jamaican Jerk Spatchcock Chicken

  • pink iced heart sugar cookies Sour Cream Sugar Cookies with Cream Cheese Frosting

Latest on Instagram

simplysogood

🍋 I teach you how to cook from scratch
🍒 Follow simple step-by-step recipes
🫐 A lover of fresh, seasonal, & local ingredients

Fresh Herb Crockpot Turkey Breast with Brown Butte Fresh Herb Crockpot Turkey Breast with Brown Butter Pears is perfect for a smaller but still impressive Thanksgiving dinner. This easy recipe features a boneless turkey breast coated in homemade herb butter and "roasted" in a slow cooker, then served with a creamy cider herb gravy and sautéed browned butter pears....

https://www.simplysogood.com/fresh-herb-crockpot-turkey-breast-with-brown-butter-pears/
These strawberry rhubarb crumble bars will take yo These strawberry rhubarb crumble bars will take you straight to dessert paradise! 🥰⁠🍓
.⁠
Sweet-tart love in every bite, they’re the perfect treat for sunny days and cozy nights. Grab a bar and let’s indulge in this fruity delight!⁠
.⁠
Give this recipe a try by clicking the link in my Instagram bio, where I post step-by-step photo instructions!
⁠
#rhubarbseason #homemadewithlove #dessertclub #strawberryrhubarb #strawberryrhubarbpie #strawberrycrumble #strawberryrhubarbcrumble
Baking up some homemade magic with my no-knead Lem Baking up some homemade magic with my no-knead Lemon Rosemary Gruyere bread!
•
This recipe is as easy as pie (or should I say bread?), bringing the flavors of tangy lemon, fragrant rosemary, and oh-so-melty Gruyere to life. 🍋🍞🌱
•
Click the link in my bio to read through these helpful tips that will make your homemade bread a melt-in-your-mouth success!

#homemadebread #nokneadbread #gruyerebread #lemoncheesebread #cheesebread #homemadecheesebread
Starting the day off right with these indulgent no Starting the day off right with these indulgent no-knead brioche morning buns! 🤎 There’s just something about the buttery, flaky brioche and the sweet cinnamon swirl that makes mornings extra special.
•
The base dough recipe for no-knead brioche morning buns is a buttery no-knead dough that is refrigerated overnight. The chilled dough is very easy to roll, fill, slice, and bake.
•
So go ahead, treat yourself to something delicious and let these buns brighten up your day! 

The recipe link is in my Instagram bio!

#MorningTreats #BriocheLove #SweetIndulgence #cinnamonsugar #cinnamonandsugar #morningbuns
No fancy Ice Cream Maker — no problem! 🍦🍨 No fancy Ice Cream Maker — no problem! 🍦🍨 This no churn Strawberry Raspberry Ice Cream recipe is quick and easy to make without an ice cream maker in only 10 minutes.
•
Simply blend together a mix of frozen strawberries and raspberries with vanilla ice cream and raspberry sherbet for a rich, fruity, and creamy dessert that tastes homemade! 🍓
•
Give this recipe a try by clicking the link in my Instagram bio, where I post step-by-step photo instructions!

#nochurnicecream #homemadeicecream #strawberryicecream #raspberryicecream #kidfriendlyrecipes #simplerecipes
These chewy peanut butter bars have been a family These chewy peanut butter bars have been a family favorite for decades! Peanut butter cookies layered with chocolate and a delicious peanut butter glaze! 🥜🍫
•
Trust me, your family will LOVE them!
•
Click the link in my bio to read through these helpful tips that will make your peanut butter bars a melt-in-your-mouth success!

#peanutbutterbars #peanutbuttercookies #pbbars #peanutbutterchocolate #peanutbutterlover #pbandchocolate
Start your day off on a flaky note with these skys Start your day off on a flaky note with these skyscraper buttermilk biscuits!
These melt-in-your-mouth treats are the perfect indulgence for breakfast, brunch, or anytime you’re craving something buttery and delicious.
•
So go ahead, treat yourself to these heavenly delights and savor every flakey, buttery bite with me!
•
The recipe link is in my Instagram bio!

#butterybiscuits #homemadeisbest #breakfastindulgence #brunchgoals
Sharing my famous Lemon Curd Recipe! 🍋🌼💛 Sharing my famous Lemon Curd Recipe! 🍋🌼💛 The one that everyone says I should sell at farmers markets — nah! I’ll just share the recipe with you all instead!
•
I love lemon curd, and use it for so many things!!
🍰 Layered in a cake
🍦 Swirled into ice cream
🍪 Smashed between cookies
☀️ Filled inside scones

The possibilities are endless!! Give this recipe a try by clicking the link in my Instagram bio! And if you’d like the recipes for my other lemon curd inspired goodies, they’re all linked in my Instagram stories!

#lemoncurd #lemoncurdcake #lemoncurdicecream #lemonicecream #lemondessert #lemoncurdrecipe
Have you ever tried an olive oil cake!? 🍰 They Have you ever tried an olive oil cake!? 🍰 They are incredibly soft and moist — you gotta give it a try!
•
This citrus olive oil cake recipe features a tart lemon curd filling and a rich mascarpone frosting. Then we gently add flowers for beautiful decoration. It is an impressive looking and mouth-watering dessert that’s perfect for any special occasion! 🍋🤍🌼

Recipe is linked in my Instagram bio!

#oliveoilcake #oliveoilcakes #lemoncurdcake #mascarponefrosting #mascarponeicing
Follow on Instagram
  • No-knead Crusty Bread in a Dutch oven No-knead Crusty Bread posted on September 19, 2018

  • Lemonade and raspberry lemonade in tall glasses Old Fashioned Lemonade posted on June 22, 2018

  • pan of frozen lemon curd ice cream with ice cream scoop No-Churn Lemon Curd Ice Cream posted on April 10, 2020

  • Lemon Curd Ice Cream in bread pan with spoon Lemon Curd Ice Cream posted on May 25, 2023

  • Large jar of spicy sweet bread and butter pickles with habanero peppers and onions. Spicy Sweet Refrigerator Pickles posted on July 22, 2019

  • Wooden board with chocolate cookies with half chocolate icing and half vanilla icing Chocolate Half Moon Cookies posted on April 5, 2024

  • Blackberry Raspberry Jam posted on September 30, 2013

  • Several chocolate drop cookies on white background Chocolate Drop Cookies posted on May 20, 2024

  • Jerk Spatchcock Chicken on wood Jamaican Jerk Spatchcock Chicken posted on May 18, 2018

  • pink iced heart sugar cookies Sour Cream Sugar Cookies with Cream Cheese Frosting posted on February 8, 2025

Footer

Featured on

The Daily Meal Logo The foodgawker-logo reddit Logo BuzzFeed Logo halfbaked Harvest Logo Browneyed Baker Logo FOOD52 Logo University of Washington Logo sheknows Logo

Copyright © 2025 Janet Barton
Privacy Policy

 

Loading Comments...
 

    Rate This Recipe

    Your vote:




    A rating is required
    A name is required
    An email is required

    Recipe Ratings without Comment

    Something went wrong. Please try again.