I’ve always loved the comforting flavor of French Onion Soup, but the traditional stovetop version felt like a lot of work. Then I tried making it in a crockpot—and wow, it changed everything!

The rich, slow-cooked flavor still shines through, and the hands-off approach makes it so easy. I made this for a weekend dinner, and everyone raved about it.

If you want that deep savory taste without hovering over the stove, this one’s for you.

Ingredients

Here’s everything I used to make this hearty Crockpot French Onion Soup. Stick with fresh ingredients for the best flavor, especially when it comes to onions and cheese.

5–6 medium yellow onions, thinly sliced – Yellow onions are naturally sweet and perfect for caramelizing. Don’t use red; they can turn bitter.
4 tablespoons unsalted butter – Helps caramelize the onions slowly and evenly.
2 tablespoons olive oil – Prevents the butter from burning and adds richness.
4 garlic cloves, minced – Fresh garlic adds a delicious savory depth.
8 cups beef broth – I went with low-sodium so I could better control the salt.
½ cup dry white wine – Optional, but it brings out incredible flavor and aroma.
2 tablespoons Worcestershire sauce – Adds umami and complexity.
1 teaspoon sugar – Speeds up caramelization and enhances sweetness.
1 teaspoon dried thyme – Gives the soup a warm, earthy note.
Salt and black pepper, to taste – Adjust according to your preference.
Baguette slices, toasted – These act as the cheesy lid that soaks up all that goodness.
1 ½ cups Gruyère cheese, shredded – Grate it fresh if you can; it melts better and tastes sharper.

Note: This recipe serves about 6 generous bowls based on the ingredient quantities above.

Variations

If you’re looking to adjust this for dietary needs or want to try something different, here are some easy swaps:

Vegetarian option: Use a rich vegetable broth and skip the Worcestershire (or use a vegetarian version).
Gluten-free version: Choose a gluten-free baguette or bread for the topping.
Dairy-free: Use plant-based butter and a dairy-free cheese that melts well.
Cheese swaps: Don’t love Gruyère? Try Swiss, provolone, or even mozzarella.

Cooking Time

Want to know how long this will take? Here’s a breakdown:

Prep Time: 20 minutes
Cooking Time: 6–8 hours on low (or 4 hours on high)
Total Time: 6.5–8.5 hours

Equipment You Need

Crockpot or Slow Cooker – This does the heavy lifting, cooking everything low and slow.
Sharp Knife – Helps slice the onions evenly for even caramelization.
Cutting Board – Gives you a solid, safe surface to work with.
Large Skillet – Essential for caramelizing the onions before slow cooking.
Ladle – Makes serving hot soup super easy and mess-free.
Oven-safe Soup Bowls – Needed if you’re topping with cheese and broiling.

How to Make Crockpot French Onion Soup?

Making this soup is easier than you’d expect. The only real work is caramelizing the onions. After that, the crockpot takes over and fills your kitchen with incredible smells.

Caramelize the Onions

First things first—slice your onions thin. Heat butter and olive oil in a large skillet over medium heat. Add the onions and sprinkle in the sugar. Stir every few minutes for about 25–30 minutes, until the onions are deeply golden and fragrant. Don’t rush this step—it’s where all that rich flavor starts.

Load the Crockpot

Once the onions are ready, pour them into your crockpot. Add the minced garlic, beef broth, white wine (if using), Worcestershire sauce, and thyme. Season with salt and pepper. Give everything a good stir so the flavors begin to mingle.

Let It Simmer Low and Slow

Cover your crockpot and set it on low for 6–8 hours or high for 4 hours. You’ll know it’s ready when your kitchen smells amazing and the onions have practically melted into the broth.

Toast the Baguette

As the soup finishes cooking, preheat your oven and toast the baguette slices until golden and crisp. This makes sure they hold up under the cheese and soup instead of going soggy.

Assemble and Broil

Ladle hot soup into oven-safe bowls. Place a toasted baguette slice on each and pile on the shredded cheese. Broil for 1–2 minutes until the cheese is melted, bubbly, and slightly golden on top.

Serve and Savor

Carefully remove the bowls from the oven—they’ll be hot! Serve immediately and enjoy every cheesy, savory spoonful. A simple green salad makes a perfect side.

Additional Tips for Making This Recipe Better

From my kitchen to yours, here are some personal tips to make this dish even better:

Always caramelize the onions slowly—don’t crank up the heat.
Grate cheese fresh from a block. It melts way better than pre-shredded.
Don’t skip the sugar when caramelizing; it makes a big difference.
Add a splash of balsamic vinegar for a tangy depth (try it once—you’ll thank me).
Make it ahead and reheat—it tastes even better the next day!

How to Serve Crockpot French Onion Soup?

Presentation makes this cozy soup even more impressive:

Serve in deep, oven-safe bowls for that classic bubbling cheese top. I like to garnish with a little extra thyme or cracked pepper before serving. Pair it with a crisp green salad or a light white wine. For a rustic feel, serve on wooden boards with extra toasted baguette on the side.

Nutritional Information

Here’s a quick peek at what’s in each serving (approximately):

Calories: 320
Protein: 14g
Carbohydrates: 28g
Fat: 18g

Make Ahead and Storage

Storing: Pour cooled soup into airtight containers and refrigerate for up to 5 days. Keep the bread and cheese separate.
Freezing: Yes, you can freeze it! Freeze just the broth (no cheese or bread) for up to 3 months.
Reheating: Gently warm the soup on the stovetop or microwave. Add fresh toasted bread and cheese before serving again.

Why You’ll Love This Recipe?

This soup became one of my favorites for so many reasons. Here’s why I think you’ll love it too:

Super easy to make – The crockpot does most of the work while you go about your day.
Big flavor payoff – Deep, savory broth with rich caramelized onions and melty cheese.
Flexible and customizable – Easily make it vegetarian, gluten-free, or change up the cheese.
Perfect for meal prep – Tastes even better the next day.
Cozy and comforting – It feels like a warm hug in a bowl on chilly days.

Ash Tyrrell