Slow Cooker French Onion Soup

Yes! You can caramelize onions in a slow cooker. And, yes! They make the most heavenly Slow Cooker French Onion Soup.


Phyllis Good's Stock the Crock cookbook is chockful of slow cooker hacks and delicious recipes like Caramelized Onions for Soup (or Sandwiches).

A complimentary digital copy of Stock the Crock by Phyllis Good was provided for review by Time Inc. Books. All opinions here are those of Flo and Grace.

The New Must-Have Slow Cooker Cookbook

Fall came on quick this year. Trees have turned overnight, there’s snow on most of our Colorado 14ers and a definite chill hangs in the evening air. These are all signals that it’s time for everything pumpkin, mid-morning pots of tea and lots of CrockPot cooking!

This week I was deliciously impressed by a slow cooker recipe from Phyllis Good’s new cookbook, Stock the Crock: 100 Must-Have Slow-Cooker Recipes 200 Variations for Every Appetite (affiliate link).

Though every recipe in this fabulously done cookbook looks like a winner, I had to start with Caramelized Onions for Soup (or Sandwiches) because I had serious doubts that caramelized onions could be made, hands-free, in a slow cooker. Well, I found out that they can! And they make a pretty fantastic slow cooker French onion soup.

A Cookbook For Every Appetite

A feature of Phyllis’ new book is that she offers suggestions for accommodating those of us who are gluten-free and dairy-free. It truly is a cookbook for everyone and every appetite (gluten-free, paleo, vegan, etc.). Sure there may be a few recipes that just don’t translate to every diet, but the majority of them do.

Phyllis Good Slow Cooker Expert

Meet Phyllis Good

If you don’t know Phyllis, she’s the most trusted name for slow cooker recipes. According to the New York Times, her books have sold more copies in the U.S. than the combined works of popular Food Network hosts Ina Garten, Giada De Laurentiis, and Jamie Oliver. This lady knows her slow cooking and it is evident in this latest cookbook.

“The bar for the recipes in this cookbook was high,” says Good. “I looked for the recipes that no slow cooker user should be without—the ones that guarantee make-it-again results. I’ve also included all the know-how that I’ve learned through the years about slow cookers and how to get them to do their best work.”

A Variety of Recipe and Flavors

Whether you want beloved classic recipes with better-for-you ingredients—no more canned, creamed or condensed soups!—or are looking for slow cooker hacks like making two recipes in your crock pot at the same time, Stock the Crock covers page after page of tricks, tips and techniques that you cannot live without. Follow the recipes in this book, and you’ll spend more time with your family and friends as you enjoy hassle-free delicious dishes, including:

  • Lasagna in a Soup Bowl
  • Cheesy Mushroom Risotto
  • Creamy Chicken, Stuffing and Green Beans
  • Swedish Meatballs from Grandma Brenneman
  • Screamin’ Good Carnitas
  • Maple Brushed Salmon
  • Salsa Rice
  • Pumpkin Spice Crème Brulee
  • Chai Apple Butter
  • Chocolate Peanut Butter Cake with Sauce
  • And much more!

With the permission of Time Inc. Books and Phyllis Good, I am excited to share the following recipe for Caramelized Onions and slow cooker french onion soup. I think you’ll love it, too!

Phyllis Good's Stock the Crock cookbook is chockful of slow cooker hacks and delicious recipes like Caramelized Onions for Soup (or Sandwiches).

Caramelized Onions for Soup (or Sandwiches)

Serves: 4 Prep Time: Cooking Time:
Nutrition facts: 200 calories 20 grams fat
Rating: 5.0/5
( 1 voted )


2 1/2 pounds red onions
1/3 cup avocado oil or olive oil
1/2 teaspoon kosher salt
A few peeled garlic cloves, optional
4 cups low-sodium vegetable broth or beef broth
2 beef bouillon cubes or 2 tablespoons beef bouillon granules
1/3 cup full-bodied red wine, optional
Salt and black pepper, to taste
Croutons or crusty bread, for topping (I make my own croutons using gluten free bread)
Your favorite melty cheese (I used SoDelicious Shreds ... they are new and pretty great!)


Grease the interior of the slow cooker crock with nonstick cooking spray.
Cut the onions in half on a cutting board, place them flat sides down, and cut them into 1/4-inch-thick slices. Place the slices in the crock. If they come almost to the top, don’t worry. They’ll sweat and shrink down.
Pour the oil and spoon the salt over the onions. Add the garlic cloves, if desired. Stir. Cover. Cook on High for 6 hours.
If you are home, stir up from the bottom after the first hour of cooking and again after another 2 hours. But if you’re away or cooking overnight, it’s not a problem.
After 6 hours, make French Onion Soup by stirring in the broth, bouillon, and, if desired, wine. Proceed with Steps 6 through 8. Or season the onions with salt and pepper to taste, and then remove them to use in sandwiches or omelets.
Cover. Continue cooking on High 1 to 2 more hours, or until the onions are tender. Remove the lid; cook 15 more minutes on High.
Season to taste with salt and pepper.
Serve in bowls. Top with the croutons or crusty bread and cheese, which will melt from the heat of the soup.


Make the onions overnight. They don’t need tending.

Follow the recipe through Step 5 for Caramelized Onions. Store them in the refrigerator for up to 3 days or freeze to use later. (Be sure to thaw frozen onions if proceeding to make soup.)

Make It Gluten-free: Use gluten-free bread or croutons.

Make It Vegetarian/Vegan: Substitute vegetable broth, preferably one with mushrooms, for the beef broth. Use a vegan cheese and sprinkle nutritional yeast on the bread.

Simple Swaps: Substitute leeks for half the onions. Switch up the toppings with different types of cheese.

A recipe from Stock the Crock by Phyllis Good, this is a wonderful shortcut to greatness! Who knew you didn’t need to slave over a stove for hours for French Onion Soup?

More Good Stuff


Jenna Urben | The Urben Life February 4, 2018 - 10:59 am

I’m so glad I came across this recipe! I’ve been wanting to FINALLY try cooking french onion soup.

Alexa February 11, 2018 - 1:46 pm

Enjoy Jenna!


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