This slow cooker onion soup is incredibly easy and flavorful. French Onion Soup is a classic dish that originated in France. It’s a savory soup made primarily with caramelized onions, beef broth, and it’s sometimes flavored with a splash of wine. While the slow cooker is not a standard method, it produces a tasty French onion soup.
Gruyère cheese, with its nutty flavor, is the classic choice for French Onion Soup, but another melty cheese may be substituted. I have used mozzarella and fontina. A slice of baguette or crusty bread is placed on the finished soup, the grated cheese is sprinkled onto it, and then the soup is placed under the broiler to melt and brown the cheese. Warm up with a piping hot bowl of onion soup!
PrintSlow Cooker Onion Soup Recipe
The slow cooker makes this onion soup a breeze to fix and cook. Choose mozzarella or Gruyere cheese for a fabulous finish.
- Prep Time: 15 minutes
- Cook Time: 5 hours 30 minutes
- Total Time: 5 hours 45 minutes
- Yield: 6 servings 1x
- Category: Soups
- Method: Slow Cooker
- Cuisine: French
Ingredients
- 5 large onions, sliced, about 40 to 45 ounces
- 1/4 cup butter
- 1 tablespoon all-purpose flour
- 6 cups beef broth
- A few drops hot pepper sauce
- 6 thick slices French bread, toasted, or croutons
- 4 ounces shredded Gruyere or Mozzarella cheese
- Salt and freshly ground black pepper, to taste
Instructions
- Melt the butter in a large skillet over medium heat. Add the onions and cook until they are transparent, stirring frequently.
- Add the flour; cook, stirring, until flour is well incorporated into the butter.
- Transfer the onion mixture to the slow cooker. Add beef broth and hot sauce. Cook on low for 5 to 7 hours or on high for 3 to 4 hours.
- Taste the soup and adjust the seasonings.
- Ladle the soup into broiler-safe bowls. Top with bread and some of the shredded cheese. Broil until the cheese is bubbly and browned.
