Slow Cooker French Onion Soup (Printable)

Caramelized onions, savory beef broth, and melted Gruyère on crispy baguette slices.

# What You'll Need:

→ Vegetables

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

→ Liquids

03 - 6 cups beef broth
04 - 1/2 cup dry white wine

→ Dairy

05 - 2 cups shredded Gruyère 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
11 - 1 bay leaf

# Directions:

01 - Melt butter in a large skillet over medium heat. Add sliced onions and cook, stirring frequently, until soft and lightly golden, approximately 10-15 minutes.
02 - Stir minced garlic into the caramelized onions and continue cooking for 1 minute until fragrant.
03 - Transfer onion mixture to slow cooker. Pour in beef broth, white wine, thyme, bay leaf, salt, and pepper. Stir thoroughly to incorporate all ingredients.
04 - Cover and cook on low setting for 6-8 hours until onions achieve deep caramelization and flavors are fully developed. Remove and discard bay leaf before serving.
05 - Preheat broiler 20 minutes before serving. Arrange baguette slices on baking sheet and toast until golden brown, 1-2 minutes per side.
06 - Ladle hot soup into oven-safe bowls. Place toasted baguette slice on top of each bowl and generously cover with shredded Gruyère cheese.
07 - Arrange bowls on baking sheet and broil until cheese becomes bubbly and golden brown, approximately 2-3 minutes. Watch carefully to prevent burning.
08 - Serve immediately while hot, garnished with additional fresh thyme sprigs if desired.

# Helpful Tips:

01 -
  • The depth of flavor you get from slow caramelized onions rivals any restaurant version
  • Most of the cooking time is hands off letting you tend to other things
  • Nothing beats breaking through that crispy cheese crust into hot savory soup
02 -
  • Skipping the initial stovetop caramelization will leave your soup tasting flat and watery
  • Oven safe bowls are non negotiable unless you want to clean up broken ceramic from your broiler
  • The soup needs to be piping hot before broiling or the cheese will burn before the soup warms through
03 -
  • Patience during the initial onion cooking pays off in the final depth of flavor
  • Use a ladle to transfer soup to bowls without disturbing all those caramelized bits at the bottom

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