Easy Caramelized French Onion Soup in the Slow Cooker
Rich, golden, and deeply flavorful, this classic French onion soup is made effortlessly in your Crock-Pot® slow cooker. Let the slow cooker do all the work to caramelize the onions to sweet perfection while you go about your day. Finish with crusty bread and melty cheese for the ultimate cozy comfort food.
Easy Caramelized French Onion Soup in the Slow Cooker
8
servings15
minutes6
hours20
minutes311
kcalIngredients
½ cup (1 stick) unsalted butter
4 large sweet onions (such as Vidalia or Spanish), thinly sliced
2 teaspoons sugar (optional, helps caramelization)
1 teaspoon salt
½ teaspoon black pepper
8 cups beef broth (or a mix of beef and chicken broth)
¼ cup dry sherry or dry white wine (optional but recommended)
1 tablespoon Worcestershire sauce
2 sprigs fresh thyme (or ½ teaspoon dried thyme)
1 bay leaf
For Serving
Baguette or French bread, sliced and toasted
2–3 cups shredded Gruyère cheese (Swiss or provolone work too)
Fresh thyme leaves or chopped parsley (optional garnish)
Directions
- Caramelize the onions
- Place butter in the bottom of your 6-quart (or larger) Crock-Pot® slow cooker. Add the sliced onions, sugar (if using), salt, and pepper. Toss everything together so the onions are coated in the melting butter. Cover and cook on LOW for 10–12 hours, stirring once or twice if you’re around. The onions should be deep golden brown and very soft. (No need to babysit—this is the beauty of the slow cooker!)
- Build the soup
- Once the onions are beautifully caramelized onions are ready, pour in the beef broth, sherry (if using), Worcestershire sauce, thyme sprigs, and bay leaf. Stir well, cover, and cook on LOW for another 1–2 hours (or on HIGH for 30–45 minutes) to let the flavors meld.
- Taste and adjust
- Remove the thyme sprigs and bay leaf. Taste the soup and add more salt or pepper as needed.
- Broil the cheesy topping (the best part!)
- Preheat your oven broiler. Ladle the hot soup into oven-safe bowls. Top each with 1–2 toasted baguette slices and a generous handful of shredded Gruyère. Place bowls on a baking sheet and broil 2–4 minutes until the cheese is bubbly and golden. Watch closely so it doesn’t burn!
Tips & Variations
- No time to broil? Use your Crock-Pot® Casserole Crock or transfer soup to a baking dish, top with bread and cheese, and bake at 425°F for 10–15 minutes.
- Make it vegetarian: Swap beef broth for rich mushroom or vegetable broth and add an extra dash of Worcestershire or soy sauce for depth.
- Freezer-friendly: Freeze the soup (without bread/cheese) for up to 3 months. Thaw and reheat, then add toppings fresh.
Warm, soul-satisfying French onion soup with almost zero active work—your slow cooker does the heavy lifting so you can enjoy restaurant-quality results at home. Perfect for chilly nights or impressing guests!
