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Crockpot French Onion Soup

Crockpot French Onion Soup

Crockpot French Onion Soup is a cozy, comforting dish made with slowly caramelized yellow onions, rich beef broth, and aromatic herbs, finished with toasted baguette slices topped with melted Gruyère cheese. Perfect for warming up on chilly evenings or serving as a delicious, effortless meal any time of year.

  • Total Time: 6 hours 30 minutes to 8 hours 30 minutes
  • Yield: 6 servings 1x

Ingredients

Scale

Soup Base

  • 6 large yellow onions, thinly sliced
  • 4 cups beef broth
  • 4 tablespoons butter
  • 3 cloves garlic, minced
  • 1 cup dry white wine
  • 2 sprigs fresh thyme
  • 2 bay leaves
  • Salt, to taste
  • Pepper, to taste

Bread and Cheese Topping

  • 8 slices baguette
  • 2 cups shredded Gruyère cheese

Instructions

  1. Slice and Prepare the Onions: Thinly slice yellow onions to ensure even cooking and caramelization throughout the slow cooking process. This foundation builds the rich depth of flavor essential to the soup.
  2. Caramelize the Onions: Melt butter in a skillet over medium heat and cook the onions slowly until golden and soft, about 15 to 20 minutes, unlocking their natural sweetness and developing the signature flavor.
  3. Combine Ingredients in the Crockpot: Transfer the caramelized onions to the crockpot. Add minced garlic, beef broth, dry white wine, thyme sprigs, bay leaves, salt, and pepper. Stir gently to combine all the flavors.
  4. Slow Cook: Set the crockpot to low and cook for 6 to 8 hours, allowing flavors to meld and onions to soften completely, resulting in a deeply flavored broth.
  5. Prepare the Bread and Cheese: About 30 minutes before serving, toast baguette slices. Top each slice with shredded Gruyère cheese and place under the broiler until cheese is bubbly and golden.
  6. Serve and Enjoy: Ladle the soup into bowls and top each with a cheesy bread slice. Garnish with chopped fresh parsley or chives, if desired, and enjoy the warm, satisfying flavors.

Notes

  • Patience is key: slow caramelization of onions is crucial for authentic sweet flavor—do not rush.
  • Use quality broth, preferably homemade or low-sodium, to control saltiness.
  • Toast bread well so it stays firm under the cheese and soup without becoming soggy.
  • Do not skip the white wine; it adds important acidity and brightness to the soup.
  • Remove bay leaves before serving to avoid bitterness.
  • Store leftover soup in an airtight container up to 3 days, keeping bread and cheese separate.
  • Freeze soup without bread and cheese; thaw overnight in fridge and reheat gently.
  • Reheat slowly over medium-low heat, adding broth or water if needed to adjust consistency.
  • Author: Lina
  • Prep Time: 30 minutes
  • Cook Time: 6 to 8 hours
  • Category: Appetizers
  • Method: Slow Cooking, Broiling
  • Cuisine: French
  • Diet: Gluten Free (omit baguette or use gluten-free bread)

Nutrition

  • Serving Size: 1 bowl with bread and cheese
  • Calories: 320
  • Sugar: 8g
  • Sodium: 700mg
  • Fat: 18g
  • Saturated Fat: 10g
  • Unsaturated Fat: 6g
  • Trans Fat: 0g
  • Carbohydrates: 28g
  • Fiber: 3g
  • Protein: 12g
  • Cholesterol: 40mg

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