Description
Slow Cooker French Onion Soup is a comforting and classic dish featuring caramelized onions simmered with beef and chicken broths, white wine, and herbs, topped with toasted baguette slices and melted Gruyère cheese. This recipe uses a slow cooker to develop deep flavors and easy preparation, culminating in a deliciously cheesy, aromatic soup perfect for cozy meals.
Ingredients
Scale
Soup Base
- 4 large yellow onions, thinly sliced
- 4 cloves garlic, minced
- 2 tablespoons olive oil
- 4 cups beef broth
- 2 cups chicken broth
- 1/2 cup dry white wine
- 1 tablespoon Worcestershire sauce
- 4 sprigs fresh thyme
- 1 bay leaf
- Salt and pepper, to taste
Topping
- 1 baguette, sliced into 1-inch pieces
- 2 cups grated Gruyère cheese
Instructions
- Prepare the onions and garlic: Peel and thinly slice the yellow onions into even rings and mince the garlic cloves to ensure even cooking and flavor distribution.
- Caramelize onions and garlic: Heat olive oil in a large skillet over medium-high heat, add the sliced onions and minced garlic, and sauté while stirring often until the onions become golden brown and caramelized, about 15-20 minutes, enhancing their natural sweetness.
- Transfer to slow cooker: Move the caramelized onions and garlic into the slow cooker and add beef broth, chicken broth, dry white wine, and Worcestershire sauce, which add richness and depth to the soup.
- Add herbs and seasoning: Place fresh thyme sprigs and a bay leaf into the slow cooker and season with salt and pepper to taste, infusing the soup with fragrant herbal notes.
- Cook the soup: Cover and cook on low for 6 to 8 hours or on high for 3 to 4 hours, allowing flavors to meld and deepen slowly for a rich soup base.
- Remove herbs: Once cooking is complete, remove the thyme sprigs and bay leaf to prevent overpowering the soup.
- Toast the baguette slices: Preheat the oven to 400°F (200°C) and toast the baguette slices for 5-7 minutes until golden and crisp, preparing them for the cheesy topping.
- Assemble the soup bowls: Ladle soup into oven-safe bowls placed on a rimmed baking sheet, top each with a toasted baguette slice, and generously sprinkle with grated Gruyère cheese for a melty topping.
- Broil the cheese topping: Place the baking sheet in the oven and broil for 3-5 minutes or until the cheese melts and bubbles, creating a perfect golden crust.
- Serve: Carefully remove the bowls from the oven, optionally garnish with fresh thyme, and serve hot to enjoy the comforting flavors.
Notes
- Caramelizing onions properly is key for the soup’s rich flavor; take your time during this step.
- Using a mix of beef and chicken broth adds complexity but you can use only one if preferred.
- For a vegetarian version, replace broths with vegetable broth and omit Worcestershire sauce or use a vegetarian alternative.
- To save time, you can caramelize onions the night before and refrigerate.
- Be careful when broiling cheese to prevent burning; watch closely during the last minutes.
- Gruyère cheese has the perfect melt and nutty flavor, but Emmental or Swiss cheese can be substituted.
