Slow Cooker Onion Soup Recipe
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The slow cooker makes this onion soup a breeze to fix and cook. Choose mozzarella or Gruyere cheese for a fabulous finish.
- Author: Diana Rattray
- 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
- 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
- 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.