French Onion Soup Slow Cooker
This Slow Cooker French Onion Soup captures all the rich flavors of traditional French onion soup without the fuss. Onions are slowly caramelized in the slow cooker and combined with beef broth, a hint of wine, and topped with toasted bread and melted cheese for an indulgent treat.
Equipment
- 1 slow cooker at least 6-quart capacity
- 1 broiler-safe oven dish or individual ramekins
- 1 cutting board
- 1 measuring cups
- 1 measuring spoons
Ingredients
- 6 large yellow onions, thinly sliced
- 4 tablespoons unsalted butter
- 2 tablespoons olive oil
- 1 teaspoon salt
- 1 teaspoon sugar
- 4 cloves garlic, minced
- 8 cups beef broth
- 1 cup dry white wine optional
- 2 tablespoons fresh thyme leaves or 2 teaspoons dried thyme
- 1 bay leaf
- 1 tablespoon Worcestershire sauce
- to taste freshly ground black pepper
- 6 slices French bread
- 2 cups shredded Gruyère cheese
Instructions
- In the slow cooker, combine the sliced onions, butter, olive oil, salt, and sugar. Stir to combine.
- Cover and cook on low for 6 hours, stirring occasionally, until the onions are deeply caramelized and golden brown.
- After 6 hours, add the minced garlic and stir well. Cook for an additional 15 minutes.
- Pour in the beef broth and wine (if using). Add thyme, bay leaf, Worcestershire sauce, and black pepper. Stir to combine.
- Cover and cook on low for an additional 30 minutes to allow the flavors to meld.
- Preheat your broiler. While the soup is cooking, toast the slices of French bread until golden brown.
- Once the soup is done, remove the bay leaf. Ladle the soup into individual oven-safe bowls or ramekins.
- Place a slice of toasted bread on top of each bowl and generously sprinkle with Gruyère cheese.
- Broil for 2-5 minutes or until the cheese is melted and bubbly. Keep a close eye to avoid burning.
- Serve immediately and enjoy!
Notes
For a vegetarian version, you can substitute the beef broth with vegetable broth.
You can add more herbs like parsley or a splash of sherry for added depth of flavor.
Leftover soup can be stored in the refrigerator for up to 3 days or frozen for up to a month.