Slow Cooker French Onion Soup

This slow cooker French onion soup is simmered until richly flavored, topped with toasted bread and a blend of cheeses, then broiled until bubbly.

• Preparation Time: 30 mins
• Cooking Time: 4 hr 45 mins
• Total Time: 5 hr 15 mins
• Calories: 250 Calories

Ingredients

• 1 tablespoon white sugar
• 6 tablespoons butter
• 1 bay leaf
• 2 cloves garlic, minced
• 4 large yellow onions, sliced and separated into rings
• 7 cups reduced-sodium beef broth
• 1 teaspoon sea salt, or to taste
• 8 slices of French bread
• 2 tablespoons shredded mozzarella cheese
• 0.25 teaspoon dried thyme
• 0.5 cup cooking sherry
• 0.5 cup shredded Gruyere cheese
• 0.33333334326744 cup shredded Emmental cheese
• 0.25 cup freshly shredded Parmesan cheese

Recipe Instructions

Step 1

Heat butter in a large, heavy pot over medium-high heat. Add onions; cook and stir until translucent, about 10 minutes. Sprinkle onions with sugar; reduce heat to medium. Cook, stirring constantly, until onions are soft and caramelized, at least 30 minutes. Stir in garlic and cook until fragrant, about 1 minute.

Step 2

Stir sherry into onion mixture; scrape the bottom to dissolve the small bits of browned food. Transfer onions into a slow cooker and pour in beef broth. Season with sea salt; stir in thyme and bay leaf. Cover and cook on Low for 8 to 10 hours or on High for 4 to 6 hours.

Step 3

Preheat the oven broiler about 10 minutes before serving. Set an oven rack about 8 inches from the heat source.

Step 4

Arrange bread slices on a baking sheet; broil until toasted, 1 to 2 minutes per side.

Step 5

Lightly toss Gruyere, Emmental, Parmesan, and mozzarella cheeses in a bowl. Fill oven-safe soup crocks 3/4 full with onion soup and float a bread slice in each bowl. Top each with about 2 tablespoons cheese mixture.

Step 6

Place filled bowls onto a baking sheet and broil until cheese topping is lightly browned and bubbling, about 2 minutes.