Best Crock-Pot French Onion Soup Recipe

A Rich and Delicious Onion Soup to Make You Smile

Onion soup topped with soft bread and gooey melted cheese is one of the tastiest things imaginable, especially on a chilly day. Fortunately, you don't have to head to your favorite restaurant to get some, because you can make onion soup yourself using a Crock-Pot. It's quite easy to put together and will fill your home with the yummy aroma of this savory dish as it cooks.

Some recipes call for a touch of sherry or beer, but this recipe is both tasty and alcohol-free, making it kid-friendly too. While the little ones may avoid eating onions in other dishes, they'll love the savory flavor of this beefy soup and the gooey fun of eating all the cheese on top. The preparation is as easy as sauteing onions and putting all the ingredients in the Crock-Pot. Start it in the morning, and come home to a steaming bowl of deliciousness that just requires a little bread and cheese on top.

Total Time: 8 hours, 45 minutes | Prep Time: 45 minutes | Serves: 8


  • 5 tablespoons butter or margarine
  • 2 tablespoons olive oil
  • 4 medium onions, thinly sliced
  • 2 garlic cloves, minced
  • 1 teaspoon brown sugar
  • 2 tablespoons flour
  • 1 tablespoon Worcestershire sauce

  • 2 teaspoons balsamic vinaigrette

  • 1/4 teaspoon pepper
  • 1/4 teaspoon fresh or dried thyme
  • 2 quarts beef broth
  • 1 bay leaf
  • French bread, sliced
  • 1 cup Gruyere or Mozzarella cheese, shredded


  1. Thinly slice the onions and mince the garlic.
  2. In a large pot over medium-high heat, cook the onions in the butter or margarine and olive oil for about 10 minutes or until translucent and slightly brown. Add the garlic, brown sugar and flour, stirring until completely blended. 
  3. Reduce heat to medium, and continue cooking the onion mixture for about 20 minutes.
  4. Add 1/2 cup of the beef broth to the pot for 2 to 3 minutes to deglaze it, incorporating all of the dark flavorful bits from the bottom of the pot.
  5. Remove the pot from the heat and pour the onion mixture into a 6-quart Crock-Pot.
  6. Stir in the Worcestershire sauce, balsamic vinaigrette, pepper, thyme and the remainder of the beef broth. Add the bay leaf.
  7. Set the Crock-Pot to low, and cook for 8 hours, or set it to high and cook for 4 hours, depending on how quickly you want it done.
  8. When the soup is finished, remove the bay leaf.
  9. Slice the French bread into 1-inch slices, and toast it until lightly browned. 
  10. Ladle the soup into oven-safe bowls and top each one with a French bread slice. 
  11. Sprinkle the shredded cheese over each bowl and place the bowls on a baking sheet. 
  12. Set the oven to broil. Place the baking sheet with the bowls in the oven for 2 to 3 minutes or until the cheese is melted and slightly browned. 
  • Use low-sodium beef broth for a healthier option, and add kosher salt to taste.
  • To avoid having to brown the onions in a separate pot, cook them along with the butter, olive oil, garlic, brown sugar and flour in the Crock-Pot, set to low, overnight for 12 hours. The next morning, add the rest of the soup ingredients, and cook on low for 8 hours or on high for 4 hours.
  • If you don't want to broil the soup bowls and cheese, simply place the French bread slices on a baking sheet and cover them with the shredded cheese. Broil them until the cheese is melted for 2 to 3 minutes in the oven, and use them to top each soup bowl.

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