Description
This Slow Cooker French Onion Soup recipe offers a comforting and deeply flavorful classic, with caramelized onions slowly cooked to perfection and topped with toasted baguette slices and melted Gruyere cheese. Ideal for an easy, hands-off dinner, it combines rich beef broth, aromatic herbs, and a touch of red wine to create a hearty and satisfying soup perfect for chilly days.
Ingredients
Scale
Soup Ingredients
- 3 large yellow onions, thinly sliced
- 1/4 cup butter, cubed
- 2 teaspoons kosher salt
- 1 teaspoon fresh ground black pepper
- 8 cups beef broth or vegetable broth
- 1/2 cup red wine
- 1 bay leaf
- 1 teaspoon dried thyme
- 2 beef bouillon cubes
- 2 teaspoons Worcestershire sauce
Toppings
- 16 slices French Baguette, sliced 1/4-inch thick
- 8 ounces Gruyere cheese, grated
- 1/4 cup grated Parmesan cheese
Instructions
- Prepare the onions: Place the thinly sliced onions, cubed butter, kosher salt, and freshly ground black pepper in your slow cooker. Cook on high for 3 to 4 hours, stirring occasionally, until the onions are tender and caramelized.
- Add liquids and seasonings: Stir the cooked onions, then add the beef or vegetable broth, red wine, bay leaf, dried thyme, beef bouillon cubes, and Worcestershire sauce to the slow cooker. Mix to combine.
- Continue cooking the soup: Cook on high for an additional 2 to 3 hours, allowing the flavors to meld and the onions to soften further, stirring occasionally.
- Prepare for serving: When ready to serve, remove the bay leaf from the soup. Ladle the hot soup into oven-safe bowls or ramekins placed on a baking sheet.
- Add bread and cheese topping: Top each bowl with two slices of French baguette and generous amounts of grated Gruyere cheese, then sprinkle with grated Parmesan cheese.
- Broil the soup: Place the baking sheet with bowls under a preheated broiler for 2 to 3 minutes, until the cheese is melted, bubbly, and golden brown. Serve immediately.
Notes
- To prepare on the stovetop: Melt butter in a large Dutch oven over medium heat. Add sliced onions and sauté for 10-12 minutes until golden and soft. Season with salt and pepper, then add broth, wine, bay leaf, thyme, bouillon cubes, and Worcestershire sauce. Bring to boil, then reduce heat and simmer uncovered for 1 hour, stirring occasionally. Remove bay leaf and serve with toasted bread and melted cheese as in steps 4 and 5.
- For a vegetarian option, use vegetable broth and omit the Worcestershire or use a vegan version.
- Be careful when broiling the cheese-topped soup bowls to avoid burning; watch closely for the perfect golden melt.
Nutrition
- Serving Size: 1 bowl (about 1 cup soup with bread and cheese)
- Calories: 320 kcal
- Sugar: 7 g
- Sodium: 750 mg
- Fat: 18 g
- Saturated Fat: 10 g
- Unsaturated Fat: 7 g
- Trans Fat: 0 g
- Carbohydrates: 28 g
- Fiber: 3 g
- Protein: 15 g
- Cholesterol: 45 mg
