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Slow Cooker French Onion Soup

Slow Cooker French Onion Soup
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Slow Cooker French Onion Soup is a comforting, hearty dish that blends the deep caramelized sweetness of onions with savory beef broth and melted Gruyère cheese. Slow-cooked for hours to develop rich, layered flavors, this easy-to-make soup is perfect for cozy dinners and casual gatherings. Customizable for dietary preferences, it delivers authentic taste with minimal hands-on prep.

Ingredients

Scale

Main Ingredients

  • 4–5 large yellow onions, thinly sliced
  • 4 cups beef broth (or mushroom/vegetable broth for vegetarian)
  • 3 tablespoons butter
  • 3–4 garlic cloves, minced
  • 2–3 sprigs fresh thyme or 1 teaspoon dried thyme
  • 2 bay leaves
  • Salt and pepper, to taste
  • 1/2 cup white wine or sherry (optional)

Toppings

  • Baguette slices, toasted
  • 1 1/2 cups Gruyère cheese, grated (or Swiss, mozzarella, provolone)

Instructions

  1. Caramelize the Onions: Slice the yellow onions thinly. In a large heavy skillet over medium heat, melt the butter and slowly cook the onions, stirring frequently, until they turn golden brown and develop a robust sweetness, about 20-30 minutes.
  2. Transfer to Slow Cooker: Move the caramelized onions to your slow cooker. Add minced garlic, thyme (fresh or dried), bay leaves, beef broth, and white wine or sherry if using. Season lightly with salt and pepper.
  3. Slow Cook to Develop Flavor: Set the slow cooker to low and let the soup simmer for 6 to 8 hours, allowing the flavors to meld and deepen.
  4. Prepare the Toppings: About 20 minutes before serving, toast baguette slices until golden and crisp. Grate the Gruyère cheese and have it ready for melting.
  5. Serve with Cheese and Bread: Ladle the hot soup into oven-safe bowls, place a toasted baguette slice on top of each, then generously cover with grated Gruyère. Broil until the cheese bubbles and forms a golden crust.

Notes

  • Use a heavy skillet for even caramelization.
  • Be patient with slow sautéing to maximize onions’ sweetness.
  • Don’t skip toasting the bread to maintain texture under cheese and soup.
  • Skim excess fat from broth occasionally for a cleaner taste.
  • Invest in good quality broth as it’s the backbone of flavor.

Nutrition

Keywords: French Onion Soup, Slow Cooker Soup, Comfort Food, Caramelized Onions, Gruyère Cheese Soup, Easy Soup, Classic French Soup

Find it online: https://marygourmet.com/slow-cooker-french-onion-soup/