French Onion Soup is a comforting, classic dish with rich, caramelized onions, savory broth, and melted cheese on top. This slow cooker version simplifies the process, letting you wake up to perfectly cooked onions, ready to be transformed into a delicious meal. Here’s how to make this crowd-pleasing recipe step by step.
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Ingredients
For the Soup:
3 pounds onions (about 6 large onions), thinly sliced
1/2 cup (4 oz) butter, melted
2 cloves garlic, minced
1/2 cup dry sherry wine (optional, but recommended for depth of flavor)
8 cups beef stock or broth (use low-sodium if desired)
1 bay leaf
1/4 tsp dried thyme (or 3 sprigs fresh; optional)
Salt and pepper to taste
For the Topping:
Baguette or French bread, sliced into 1/2-inch thick pieces
Olive oil for brushing
8 oz Gruyère cheese, shredded (or a combination of Gruyère and another melting cheese like Swiss or Mozzarella)
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Instructions
1. Caramelize the Onions in the Slow Cooker
1. Cut the onions in half, then slice them thinly. Place them in the slow cooker.
2. Add the melted butter and stir to coat all the onions evenly.
3. Cook on low for 10-12 hours overnight. The onions should become golden brown, soft, and caramelized.
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2. Build the Soup
1. Add minced garlic to the slow cooker with the caramelized onions and stir.
2. Pour in the dry sherry and scrape the bottom of the slow cooker to deglaze, ensuring all browned bits are dissolved into the mixture.
3. Add the beef stock, bay leaf, and thyme (if using). Stir everything together.
4. Cook the soup on low for 8-10 hours or high for 4-6 hours.
Tip: Adjust seasoning to taste once the soup is finished cooking. If your broth is already salted, you may not need additional salt.
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3. Prepare the Bread
1. Preheat the oven to 400°F (200°C).
2. Slice the bread into 1/2-inch thick pieces. Lightly brush both sides with olive oil.
3. Arrange the bread slices on a baking sheet and bake for 6-8 minutes, flipping halfway through, until golden brown at the edges.
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4. Assemble and Broil
1. Set your oven to broil.
2. Pour the soup into oven-safe bowls, filling them about 3/4 full.
3. Sprinkle a small amount of shredded Gruyère cheese on top of the soup. Place a toasted bread slice on top of each bowl, then sprinkle the remaining Gruyère generously over the bread.
4. Place the bowls under the broiler for 2-3 minutes, until the cheese is bubbly and golden brown.
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Serving Suggestions
Serve the French Onion Soup immediately, garnished with fresh thyme or parsley if desired. Pair it with a simple green salad or a glass of red wine for an elegant yet cozy meal.
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Tips for Success
1. Onion Selection: Yellow or sweet onions work best for this recipe, as they caramelize beautifully.
2. Make Ahead: The soup can be made ahead of time and reheated, but add the bread and cheese topping just before serving.
3. Cheese Options: Gruyère is the classic choice, but feel free to mix it with Swiss, Mozzarella, or Parmesan for variety.
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Why You’ll Love This Recipe
Hands-Free Cooking: The slow cooker handles most of the work.
Rich and Savory Flavor: Caramelized onions, beef broth, and melted cheese create the ultimate comfort food.
Perfect for Entertaining: This recipe is easy to scale up for larger gatherings.
