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–+ servings

French Onion Soup Crockpot Recipe

This crockpot French onion soup slowly cooks sweet onions in butter and beef broth until rich and savory, then finishes with toasted bread and melted cheese for a cozy, classic comfort soup made easy in the slow cooker.
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Author Kori
Prep Time 10 minutes
Cook Time 9 hours
Total Time 9 hours 10 minutes
Course Slow Cooker Soup and Stew Recipes
Cuisine American
Servings 6
Calories 417 kcal

Ingredients
  

  • 2 large thinly sliced sweet onions (about 4 cups)
  • ¼ cup butter
  • 32 ounces beef broth
  • 2 teaspoons beef soup base (or 2 to 3 beef bouillon cubes)
  • ¼ cup sherry or additional beef broth
  • ½ tablespoon red wine vinegar
  • 2 teaspoons Worcestershire sauce
  • 1 teaspoon kosher salt (plus extra to taste)
  • ½ teaspoon ground black pepper (plus extra to taste)
  • 4 slices French bread (½ inch thick), toasted
  • 4 slices Swiss cheese (provolone may be used instead)

Instructions
 

  • Lightly coat a 1½- to 2-quart slow cooker with cooking spray. Add the sliced onions and scatter the butter over the top. Cover and cook on LOW for 6 to 7 hours, stirring once or twice if possible, until the onions are very soft and lightly golden.
    Adding the sliced onions and butter to a white round slow cooker to caramelize for crockpot French onion soup.
  • Pour in the beef broth, beef base or bouillon, sherry, vinegar, Worcestershire, salt, and black pepper. Stir to combine. Cover and continue cooking on LOW for 2 to 3 more hours, until the soup is hot. Adjust seasoning to taste.
    Adding broth and spices to a white oval slow cooker for crockpot French onion soup and placing the lid on the top.
  • Ladle the soup into oven-safe bowls. Top each with a slice of toasted French bread and a slice of cheese. Place bowls on a baking sheet, then BROIL for 2 to 3 minutes, just until the cheese is melted and bubbly. Serve immediately.
    Using a black ladle to serve crockpot French onion soup in a small round white crock and garnishing with cheese and bread with a silver spoon.

Notes

For more helpful hints, substitution ideas, slow cooking tips, and other delicious recipe ideas, check out my post above.
CROCKPOT COOKING TIPS: Every slow cooker heats a little differently, so cooking times can vary. Once you know how your crock pot runs (hotter or cooler), you can adjust as needed. 
TIPS: Slice onions evenly for consistent cooking, and allow the full slow-cook time so the onions fully soften and develop their natural sweetness.
VARIATIONS: Swap provolone for Swiss or Gruyère, or skip the sherry and use extra beef broth for a non-alcoholic version.
SERVING SUGGESTIONS: Serve as a starter with a simple green salad or pair with a sandwich for an easy soup-and-supper meal.

Nutrition

Calories: 417kcalCarbohydrates: 46gProtein: 15gFat: 19gSaturated Fat: 11gPolyunsaturated Fat: 1gMonounsaturated Fat: 5gTrans Fat: 0.5gCholesterol: 46mgSodium: 1286mgPotassium: 407mgFiber: 3gSugar: 11gVitamin A: 499IUVitamin C: 8mgCalcium: 235mgIron: 3mg
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