Description
This slow cooker French onion soup delivers deep, caramelized flavor with minimal effort. It’s a comforting, crowd-pleasing weeknight dinner that requires just 15 minutes of prep and lets the slow cooker do the work.
Ingredients
Scale
- 6 large yellow onions (about 3–4 lbs / 1.5–2 kg), sliced
- 3 tablespoons unsalted butter
- 6 cloves garlic, minced
- 4 cups beef broth (low-sodium recommended)
- 2 tablespoons dry sherry
- 1 teaspoon dried thyme (or 1 tablespoon fresh)
- 1 bay leaf
- 1 teaspoon soy sauce
- 1 teaspoon Worcestershire sauce
- 1 loaf French baguette, sliced
- 2 cups Gruyère cheese, shredded
- Optional: ½ teaspoon red pepper flakes
- Optional: Fresh parsley for garnish
Instructions
- Peel and thinly slice the onions. Place them in a large bowl.
- Add the sliced onions, butter, minced garlic, beef broth, dry sherry, thyme, bay leaf, soy sauce, and Worcestershire sauce to the slow cooker. Stir to combine.
- Cover and cook on LOW for 6 to 8 hours, until onions are deep golden brown and tender. Do not cook on HIGH.
- About 30 minutes before serving, preheat the broiler. Slice the baguette and toast the slices until crisp and golden.
- Remove the bay leaf from the soup. Ladle the hot soup into broiler-safe bowls.
- Top each bowl with a slice of toasted bread and a generous amount of shredded Gruyère cheese.
- Place bowls on a baking sheet and broil for 2-4 minutes until cheese is bubbly and spotted with brown. Watch closely to prevent burning.
- Serve immediately while the cheese is gooey and the soup is steaming.
Notes
For a vegetarian version, swap beef broth for vegetable or mushroom broth. For gluten-free, use gluten-free bread. For dairy-free, use olive oil and vegan cheese. Toasting the bread before adding cheese prevents sogginess. Do not freeze the soup with the bread and cheese topping.
- Prep Time: 15 minutes
- Cook Time: 6-8 hours
- Category: Main Course
- Cuisine: French
Nutrition
- Serving Size: 1 bowl
- Calories: 380
- Sugar: 12
- Sodium: 850
- Fat: 20
- Saturated Fat: 10
- Carbohydrates: 32
- Fiber: 4
- Protein: 18
Keywords: crockpot french onion soup, slow cooker soup, easy weeknight dinner, french onion soup recipe, comfort food, vegetarian french onion soup