Slow-Cooked French Onion Soup
A classic dish that warms the soul with sweet, caramelized onions, savory broth, and a cheesy topping.
Ingredients
Onion Base
- 4 large large onions, thinly sliced
- 2 tablespoons butter
- 1 tablespoon olive oil
- 1 teaspoon salt
- 1 teaspoon sugar
Soup Ingredients
- 4 cups beef broth
- 1 cup white cooking liquid
- 2 teaspoons fresh thyme or 1 teaspoon dried thyme
- 1 bay leaf
Serving
- 1 loaf French bread, sliced
- 1.5 cups grated Gruyère cheese Generous topping for each bowl.
Instructions
Preparation
- Add butter and olive oil into the slow cooker and set it to low heat.
- Slice onions thinly and toss them into the slow cooker with salt and sugar. Stir until well coated.
Cooking Onions
- Cook onions on low for about 8 hours until caramelized.
Building Flavors
- After 8 hours, stir in beef broth, cooking liquid, thyme, and bay leaf.
- Cover and let it simmer for an additional 2 hours.
Serving
- Ladle hot soup into oven-safe bowls and top with a slice of French bread.
- Cover generously with Gruyère cheese and broil until melted and golden.
- Let cool slightly before serving.
Notes
For optimal caramelization, avoid overcrowding the slow cooker. Let the soup sit for a few hours before serving for deeper flavors. Can be modified to vegetarian by using vegetable broth and a plant-based cheese alternative.