Slow Cooker French Onion Soup (Printable Version)

Rich and comforting classic with caramelized onions, savory broth, and melted Gruyère atop crusty bread.

# What You 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)
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)
11 - 1 bay leaf

# How-To:

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

# Expert Hints:

01 -
  • The slow cooker does all the heavy lifting while you go about your day
  • You get that restaurant depth of flavor without spending hours actively cooking
  • Its incredibly forgiving and adapts easily to whatever cheese or bread you have on hand
02 -
  • Take those extra 10 minutes to caramelize the onions first because it makes a huge difference in the final depth of flavor
  • Use oven-safe bowls for the final broiling step, otherwise you'll be transferring soup and making a mess
  • Let the soup cool for just a minute after broiling because that cheese stays dangerously hot
03 -
  • Make a double batch because this reheats beautifully for lunch the next day
  • Freeze the soup without the bread and cheese for up to three months

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