Slow Cooker French Onion Soup (Print version)

Rich French onion soup with caramelized onions, beef broth, and melted Gruyère cheese on crusty bread.

# Ingredient List:

→ 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 tbsp unsalted butter

→ Breads

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

→ Seasonings

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

# How To Make It:

01 - In a large skillet over medium heat, melt the butter. Add sliced onions and cook, stirring frequently, until onions are soft and lightly golden, about 10-15 minutes.
02 - Add garlic to the 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 for 6-8 hours until onions are deeply caramelized and flavors have 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 a generous amount of Gruyère cheese.
07 - Place bowls on a baking sheet and broil until cheese is bubbly and golden, 2-3 minutes. Watch carefully to prevent burning.
08 - Serve hot, garnished with extra thyme if desired.

# Expert Advice:

01 -
  • The slow cooker does all the heavy lifting while you go about your day
  • Those deeply caramelized onions taste like they've been cooking for hours in a restaurant kitchen
  • The crispy bread and melted cheese topping turns humble soup into something special
02 -
  • Patience during the initial onion caramelization makes all the difference in depth of flavor.
  • Use oven safe bowls or the broiler step will end in disaster.
  • The soup tastes even better the next day as flavors continue developing.
03 -
  • Add a splash of sherry right before serving for restaurant quality depth.
  • Use vegetarian broth to make this completely meat free.

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