Slow Cooker French Onion Soup

Slow Cooker French Onion Soup

We love that this Slow Cooker French Onion Soup is easy to put together in the morning and makes your house smell amazing all day long!
Prep Time 10 minutes
Cook Time 9 hours
Total Time 9 hours 10 minutes
Servings 6 servings


  • 3 onions, sliced thinly
  • 3 Tbsp butter
  • 3 Tbsp flour
  • 1 Tbsp Worcestershire sauce
  • 1 tsp sugar
  • 8 cups beef broth
  • 8 slices french bread
  • 3/4 cup grated gruyere cheese


  • In your slow cooker add the butter and onions. Cover and cook on HIGH until onions brown around the edges, about 30-35 minutes.
  • Meanwhile, mix together the flour, Worcestershire sauce, sugar, and pepper. Stir the flour mixture into the onions. Add the brother and cover and cook until onions are very tender, about 7-9 hours on LOW.
  • Once the soup is done, preheat your broiler to high. Place shredded cheese on the pieces of bread and broil until melted. Place a piece of bread on each bowl of soup and serve.


Don't have all day? Cook this soup on HIGH for 4-5 hours.
Use a wooden spoon to get all of the browned pieces at the bottom of the pot when adding the flour. That's the best stuff!

Perfect Pairing

Serve this Slow Cooker French Onion Soup with Kentucky Mulled Cider.
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