I have always been a little nervous about making French onion soup. It always overwhelmed me a little, and I thought it would be complicated. But ever since I started making it in the slow cooker, I have realized just how easy it is. And it tastes as good as a five-star restaurant! You only need 6 simple ingredients for this flavor-packed soup!

A bowl of French onion soup topped with melted, golden-brown cheese sits on a wooden surface next to slices of bread, a blue cloth, and metal spoons.

Prep Time	Cook Time	Servings	Prep Level
10 minutes	8 hours	4	Beginner +

What You’ll Love About This Slow Cooker Version

French onion soup has a reputation for being sort of fussy because you have to caramelize the onions on the stove, and it can be a bit of an art form (which I am not good at). The slow cooker makes it so much easier and you can skip all those steps.

You can cook it low-and-slow, it’s budget-friendly, and it has that classic cheesy toast topping that we all love.

And just so we’re clear on timing (because this is where other recipes get confusing): this recipe cooks on LOW for 8 hours total. You’re not cooking onions overnight and then cooking the soup another 6–8 hours. It’s one stretch of time.

A bowl of French onion soup topped with melted, golden-brown cheese, with cheese dripping over the sides. Slices of toasted bread and a spoon are next to the bowl on a wooden surface.

How To Make Crock Pot French Onion Soup

This is very much a beginner recipe. If you can slice onions and stir a slow cooker, you’ve got it.

Sliced white onions covered with a layer of dry seasoning and breadcrumbs in a black rectangular dish, ready for cooking.

Start by slicing and adding the onions to the slow cooker and sprinkle the French onion soup mix on top. It seems like an overload of onions here, but they will cook down quite a bit.

White onions are the way to go here. They cook down beautifully and give you that classic French onion soup flavor without getting overly sweet.

A close-up of sliced raw onions sprinkled with spices and seasonings, showing rings and layers mixed together.

Next, add the beef broth and beef consommé. Cover and cook on low for 8 hours. Cooking on low is going to give the onions time to soften and sweeten. If you cook it on high, you will get soft onions, but the flavor won’t be as good.

Why consommé matters – Beef consommé brings a deeper, more concentrated beef flavor than broth alone. It’s one of those old-school pantry items that makes a noticeable difference without adding extra work.

Salt Note – Between the consommé and the soup mix, there’s plenty of built-in seasoning. Don’t add extra salt up front. Taste it at the end first.

A bowl of French onion soup topped with a slice of crusty bread, with sliced onions visible in the dark broth, placed on a blue cloth and wooden surface.

Add the soup to oven-safe bowls and add a slice of French bread right on top.

A bowl containing dark broth topped with several slices of Swiss cheese, with a piece of bread and a blue cloth in the background.

Place three slices of Swiss cheese right on top.

Two bowls of French onion soup topped with melted, slightly browned cheese sit on a foil-lined baking sheet. The bowls are placed side by side on a wooden table.

I like to line a pan with some aluminum foil so that when the liquid or cheese drips over, it won’t make a huge mess. Add your bowls to the pan and place them into the oven under the broiler, and cook until the cheese is golden and bubbly. I put the broiler on high, so they will cook fast.

TIP: If you’re anything like me and you get distracted for “just a second,” set a 1-minute timer and stay put. No folding laundry. No checking your phone. Just you and that broiler (speaking from experience).

Julie’s Tips For Getting The Topping Just Right

That cheese-and-bread topping is the whole point. Here’s how to make it work smoothly.

Use oven-safe bowls – This sounds obvious until you’re holding a ladle of soup and realizing your favorite bowls aren’t broiler-safe. If you’re unsure, use a sturdy ramekin or a small baking dish and just portion it out.

Toast texture – If you like crunchier toast, you can lightly toast the bread slices before topping the soup. I don’t always do it (because, hello, kids and chaos), but it helps the bread hold up longer.

Cheese coverage – Three slices per bowl sounds like a lot, but Swiss melts down, and you want the bread fully covered so it doesn’t dry out under the broiler. Belive me, you’ll be happy with three.

A close-up of French onion soup in a bowl, topped with melted cheese and toasted bread, with a spoon lifting a cheesy, onion-filled portion over the bowl. A blue cloth is in the background.

FAQs

Can I use bone broth instead of beef broth?

Yes. Use the same amount (32 oz). Bone broth can be saltier depending on the brand, and it sometimes has a more “roasty” flavor.

Do I caramelize the onions first?

Not for this recipe. The slow cooker handles the long, slow cooking for you. You’re not standing at the stove stirring for 30 minutes, and you still get that soft, sweet onion base.

Why does my soup sometimes taste too sweet?

Two common reasons. Sweet onions (like Vidalia) were used instead of white onions, or the onions were cooked down extra long and got very sweet.

Can I use less broth if I want it stronger?

You can, but here’s the truth: less broth also means less soup, and the seasoning (consommé and soup mix) becomes more concentrated.

If you reduce the broth, do it modestly and keep the same ratio in mind. I recommend starting by reducing the beef broth a little (not the consommé), and then adjust next time if you want it even stronger.

What’s the best cheese for French onion soup?

Typically, people use Gruyère, but I like to use Swiss because it tastes great. It melts well and gives you that stretchy, bubbly top.

Can I broil the bread and cheese separately instead of on the bowls?

Yes, and it’s a great option if you don’t have oven-safe bowls. Put the bread slices on a baking sheet, add Swiss on top, broil until bubbly, and then set the cheesy toast on the soup.

A close-up of a bowl of French onion soup, topped with melted, golden-brown cheese, sitting on a blue cloth next to a slice of bread and a spoon on a wooden surface.

Crock Pot French Onion Soup with Swiss Toasts

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Take a hard dish and make it easy with this Crock Pot French Onion Soup recipe. You only need a few ingredients and the slow cooker does all the cooking.

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Prep Time 10

Cook Time 8

Total Time 8 10

Course Main Dishes

Cuisine American

Servings

Calories 593 kcal

Ingredients

6 white onions sliced
20 ounces beef consommé I use two 10 ounce cans
32 ounces beef broth
1.4 ounces packet dry French onion soup/dip mix
12 slices Swiss cheese
1 loaf French bread sliced

Instructions

Slice the onions and add them to the slow cooker.
Sprinkle the French onion soup mix over the onions. Pour in the beef broth and beef consommé and stir to combine.
Cover and cook on LOW for 8 hours.
Ladle the soup into oven-safe bowls. Set a slice of French bread on top of each, then layer with 3 slices of Swiss cheese.
Slide the bowls under the broiler until the cheese is bubbly and golden brown. (It cooks fast!)

Video

Notes

Nutrition is approximate.

Nutrition

Serving: 1Calories: 593kcalCarbohydrates: 70gProtein: 32gFat: 21gSaturated Fat: 11gPolyunsaturated Fat: 1gMonounsaturated Fat: 4gCholesterol: 47mgSodium: 1884mgPotassium: 779mgFiber: 5gSugar: 13gVitamin A: 427IUVitamin C: 12mgCalcium: 582mgIron: 5mg

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