Let your slow cooker do most of the work for you when it comes to this slow cooker French onion soup. At the end, top it off with bread and cheese for a good broil and you are ready to eat.
We’re not that far into fall and I’ve already been cranking out the soup recipes. In particular, the slow cooker soups. You just can’t go wrong with a big pot of soup waiting for you at the end of the day, can you?!
I’ve been especially craving hot comfort food. Which brings us to: Slow Cooker French Onion Soup! 
While I already have a delicious recipe for French Onion Soup on here (click here for the recipe), it’s one that requires a lot of hands-on time. The onions are slowly cooked in the oven for over two hours and then the soup takes another hour to cook on the stovetop. That’s a lot of time hanging around the kitchen and while it’s true that French Onion Soup takes some time to develop flavors (and that recipe is completely worth it) I wanted to come up with a method in the slow cooker that was less hands on.
This recipe actually requires more time overall, but it’s far less work, as you let the slow cooker do it all for you. To begin with, you caramelize the onions in your slow cooker overnight. Did you know your slow cooker can do that for you?!
You simply put your onions, some butter, and salt in the slow cooker and let it go all night long on low. When you wake up your kitchen will not only smell lovely, but you’ll have deep brown caramelized onions.
After the onions are caramelized, you add the remaining ingredients of the soup and let it cook all day. Easy, right?!
To top it off, I think the bread and cheese is crucial for French onion soup. While I’ve used many recipes that simply put the bread and cheese on top and broil it, this recipe actually bakes it for 20 minutes and then broils it. This allowed the bread to really meld into the soup, and there wasn’t one bit of the bread that hadn’t soaked up the delicious broth.
Can I just say this soup got me the slightest bit excited for chilly weather?! I love a good hot day but after having this French onion soup, I’m craving a chill in the air.
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Easy Slow Cooker French Onion Soup
- Total Time: 1100 minutes
- Yield: Serves 6
- Diet: Omnivore
Description
Comfort food at its finest! This slow cooker soup simmers all day, then broils to perfection with cheesy bread.
Ingredients
- 3 lbs (1361 g) white onions
- 8 tbsp unsalted butter
- 1 tsp salt
- 8 cups (1893 ml) beef broth
- 1 tbsp Worcestershire
- 1/4 cup white wine
- 1 tbsp red wine vinegar
- 4 sprigs thyme
- Loaf of Italian bread
- 2 cups (473 ml) shredded Gruyere cheese
Instructions
- Place onions, butter, and salt in a large slow cooker.
- Cook on low for 8-10 hours.
- Add beef broth, Worcestershire sauce, wine, red wine vinegar, and thyme.
- Season with salt and pepper to taste.
- Cover and cook on low for another 6-8 hours.
- Preheat oven to 350°F (177°C).
- Place oven-proof bowls onto a baking sheet.
- Ladle soup into oven-proof bowls.
- Top with 1-2 slices of bread and ~1/4 cup of shredded cheese per bowl.
- Bake in the preheated oven for 20 minutes.
- Broil until golden brown, watching carefully.
- Garnish with additional thyme leaves.
Notes
- For deeper flavor, caramelize the onions on the stovetop for 20-30 minutes before adding them to the slow cooker.
- If you don’t have Gruyere, a blend of Swiss and cheddar cheeses makes a delicious substitute.
- To prevent soggy bread, toast the bread slices lightly before adding them to the soup.
- Prep Time: 20 minutes
- Cook Time: 1080 minutes
- Category: Soup
- Method: Braising
- Cuisine: French-Inspired
Nutrition
- Serving Size: 1.5 cups
- Calories: 350
- Sugar: 5
- Sodium: 800
- Fat: 20
- Saturated Fat: 12
- Unsaturated Fat: 6
- Carbohydrates: 35
- Fiber: 4
- Protein: 10
- Cholesterol: 50
Frequently Asked Questions
How do I caramelize the onions in the slow cooker?
To caramelize the onions, simply add sliced onions, butter, and salt to your slow cooker, then set it on low and let it cook overnight.
What type of bread works best for topping the soup before broiling?
A sturdy bread like a baguette or sourdough works best for topping the soup, as it holds up well to the cheese and the broiling process.
Can I use a different type of cheese instead of what is suggested for the topping?
Yes, you can substitute with other cheeses like Gruyère or mozzarella, but keep in mind that the flavor and melt quality may vary.
