Go Back
How to Make French Onion Soup in a Slow Cooker: Easy Crockpot Recipe

How to Make French Onion Soup in a Slow Cooker: Easy Crockpot Recipe

This easy Crockpot French Onion Soup recipe results in a rich, flavorful soup perfect for a cozy night in. Serve it with crusty bread and melted cheese for a classic finish.
No ratings yet
Rate This Yum Pin This Recipe For Later! Share The Yum On Facebook Print
Prep Time: 15 minutes
Cook Time: 8 hours
Total Time: 8 hours 15 minutes
Servings: 6
Calories: 120kcal

Ingredients
 

Main Ingredients

  • 3 pounds yellow onions thinly sliced
  • 1 tablespoon olive oil or butter
  • 2 teaspoons sugar to aid in caramelizing
  • 8 cups beef broth low sodium
  • 1 cup dry white wine optional
  • 2 tablespoons balsamic vinegar
  • 1 teaspoon thyme dried
  • 0.5 teaspoon black pepper freshly ground
  • 1 loaf French bread sliced, toasted
  • 2 cups Gruyere cheese grated

Instructions

Preparation Steps

  • Heat olive oil in a large skillet over medium heat. Add sliced onions and sugar. Cook, stirring often, for about 15 minutes until onions are soft and caramelized.
  • Transfer caramelized onions to the slow cooker. Add beef broth, wine, balsamic vinegar, thyme, and black pepper. Stir to combine.
  • Cover and cook on low for 8 hours until flavors meld together beautifully.
  • Preheat broiler. Ladle soup into oven-safe bowls. Top each with a slice of French bread and grated Gruyère cheese.
  • Place bowls under the broiler until the cheese is bubbly and golden. Serve hot.

Notes

For a vegetarian option, replace beef broth with vegetable broth.