Slow Cooker French Onion Soup (Printable version)

Rich, comforting slow cooker version with caramelized onions, beef broth, and melted Gruyère on crusty bread.

# What You'll Need:

→ Vegetables

01 - 5 large yellow onions, thinly sliced
02 - 2 cloves garlic, minced

→ Liquids

03 - 6 cups beef broth (or vegetable broth for vegetarian)
04 - 1/2 cup dry white wine (optional)

→ Dairy

05 - 2 cups shredded Gruyère cheese (or Swiss cheese)
06 - 2 tablespoons unsalted butter

→ Breads

07 - 1 baguette, sliced into 1/2-inch rounds

→ Seasonings

08 - 1 teaspoon salt
09 - 1/2 teaspoon black pepper
10 - 2 teaspoons fresh thyme leaves (or 1 teaspoon dried thyme)
11 - 1 bay leaf

# How to Prepare:

01 - Melt butter in a large skillet over medium heat. Add sliced onions and cook, stirring frequently, until onions are soft and lightly golden, about 10-15 minutes.
02 - Add minced garlic to the caramelized onions and cook for 1 minute more until fragrant.
03 - Transfer the onions and garlic to the slow cooker. Add beef broth, white wine if using, thyme, bay leaf, salt, and pepper. Stir to combine all ingredients.
04 - Cover and cook on low setting for 6-8 hours until onions are deeply caramelized and flavors have fully melded. Remove and discard bay leaf before serving.
05 - About 20 minutes before serving, preheat broiler. Arrange baguette slices on a baking sheet and toast until golden, 1-2 minutes per side.
06 - Ladle hot soup into oven-safe bowls. Top each with a toasted baguette slice and generous amount of Gruyère cheese. Place bowls on baking sheet and broil until cheese is bubbly and golden, 2-3 minutes.
07 - Serve immediately while hot, garnished with extra fresh thyme sprigs if desired.

# Expert advice:

01 -
  • The slow cooker does all the hard work of transforming onions into sweet, golden perfection while you go about your day
  • That first spoonful with melted Gruyère and crusty bread is pure comfort in a bowl
02 -
  • The onions need time to caramelize properly, do not rush this step or you will miss the deep sweetness that makes this soup special
  • Use oven-safe bowls for the broiling step, otherwise you will have a melted mess on your hands
03 -
  • Do not skip the initial onion sauté, even though it takes extra time, it builds a foundation of flavor that the slow cooker alone cannot achieve
  • Grate your own cheese instead of buying pre shredded, it melts so much better and creates that perfect bubbly topping

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