4.17 from 6 votes

{Crock Pot} French Onion Soup

Servings 6
Calories 518kcal
Author Aubrey @Real Housemoms


  • 6 tablespoons butter
  • 4 large yellow onions sliced and separated into rings
  • 1 tablespoon white sugar
  • 2 cloves garlic minced
  • 1/2 cup cooking sherry
  • 7 cups reduced-sodium beef broth
  • 1 teaspoon sea salt or to taste
  • 1/4 teaspoon dried thyme
  • 1 bay leaf
  • 8 slices of French bread
  • 1/2 cup shredded Gruyere cheese
  • 1/3 cup shredded Emmental cheese or swiss
  • 1/4 cup freshly shredded Parmesan cheese
  • 2 tablespoons shredded mozzarella cheese


  • Heat butter in a large, heavy pot over medium-high heat; cook and stir onions until they become translucent, about 10 minutes
  • Sprinkle onions with sugar; reduce heat to medium
  • Cook, stirring constantly, until onions are soft and browned, at least 30 minutes Stir in garlic and cook until fragrant, about 1 minute
  • Stir sherry into onion mixture and scrape bottom of pot to dissolve small bits of browned food from the pot
  • Transfer onions into a slow cooker and pour in beef broth
  • Season to taste with sea salt; stir in thyme and bay leaf
  • Cover cooker, set on High, and cook 4 to 6 hours (or low for 8 to 10 hours)
  • About 10 minutes before serving, set oven rack about 8 inches from the heat source and preheat the oven's broiler
  • Arrange bread slices on a baking sheet
  • Broil bread slices until toasted, 1 to 2 minutes per side
  • Combine Gruyere, Emmental (or swiss), Parmesan, and mozzarella cheeses in a bowl, tossing lightly
  • Fill oven-safe soup crocks 3/4 full of onion soup and float a bread slice in each bowl
  • Top with about 2 tablespoons of cheese mixture per serving
  • Place filled bowls onto a baking sheet and broil until cheese topping is lightly browned and bubbling, about 2 minutes


Calories: 518kcal | Carbohydrates: 58g | Protein: 23g | Fat: 20g | Saturated Fat: 12g | Cholesterol: 54mg | Sodium: 1588mg | Potassium: 799mg | Fiber: 3g | Sugar: 7g | Vitamin A: 570IU | Vitamin C: 5.9mg | Calcium: 294mg | Iron: 3.4mg