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Chicken French Onion Soup Slow Cooker

Kathleen ron
This Chicken French Onion Soup Slow Cooker Recipe is a delicious twist on the French classic, combining the rich caramelized onions and melted Gruyère cheese of traditional French onion soup with tender slow-cooked chicken. The result? A hearty, flavorful soup that’s effortless to prepare and perfect for cozy dinners, meal prep, or special occasions.
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Prep Time 15 minutes
Cook Time 7 hours
Total Time 7 hours 15 minutes
Course Soup
Cuisine French
Servings 6 people

Equipment

  • Slow Cooker (6-quart recommended) For effortless cooking and deep flavor development.
  • Sharp Knife & Cutting Board For slicing onions and prepping chicken.
  • Wooden Spoon To stir and evenly distribute ingredients.
  • Oven-Safe Bowls Essential for broiling the cheese topping.
  • Baking Sheet To toast baguette slices.

Ingredients
  

For the Soup:

  • 4 boneless skinless chicken thighs or breasts
  • 4 large yellow onions thinly sliced
  • 3 tbsp butter unsalted
  • 6 cups beef broth or chicken broth for a lighter version
  • ½ cup dry white wine e.g., Sauvignon Blanc
  • 2 cloves garlic minced
  • 1 tsp salt adjust to taste
  • ½ tsp black pepper
  • 1 sprig fresh thyme or ½ tsp dried thyme
  • 2 bay leaves

For the Topping:

  • 1 baguette sliced into 1-inch rounds
  • 2 cups Gruyère cheese shredded (or Swiss/Emmental as alternatives)
  • ¼ cup Parmesan cheese optional, for extra sharpness
  • 1 tbsp butter for brushing baguette slices

Optional Flavor Enhancers:

  • 1 tbsp balsamic vinegar for added sweetness
  • 1 tbsp brandy or cognac for depth
  • Extra thyme sprigs for garnish

Instructions
 

1️⃣ Prepare the Onions:

  • Peel and thinly slice 4 large yellow onions into even rounds.
  • In a large skillet, melt 3 tbsp butter over medium heat.
  • Add the onions and cook, stirring occasionally, for 10-15 minutes until soft and lightly golden.
  • Reduce heat to low and caramelize onions for an additional 25-30 minutes, stirring occasionally.
  • Add 1 tbsp balsamic vinegar in the last 5 minutes for deeper flavor.

2️⃣ Prepare the Chicken:

  • Trim any excess fat from the chicken thighs or breasts.
  • Season both sides with salt, pepper, and thyme.
  • (Optional) Sear the chicken in a hot skillet with a little oil for 2 minutes per side for extra flavor.

3️⃣ Assemble the Ingredients in the Slow Cooker:

  • Spread the caramelized onions evenly at the bottom of the slow cooker.
  • Place the chicken on top of the onions.
  • Pour in 6 cups of broth and ½ cup of dry white wine.
  • Add garlic, thyme, bay leaves, salt, and pepper.
  • Cover and cook on LOW for 6–8 hours (or HIGH for 3–4 hours).

4️⃣ Prepare the Cheese Toast Topping:

  • Preheat your oven to 375°F (190°C).
  • Arrange baguette slices on a baking sheet and brush lightly with butter.
  • Toast for 8-10 minutes until golden and crisp.

5️⃣ Assemble & Broil the Soup:

  • Remove bay leaves and thyme sprigs from the soup.
  • Shred the chicken with two forks directly in the slow cooker.
  • Ladle hot soup into oven-safe bowls.
  • Top each bowl with a toasted baguette slice and a generous amount of shredded Gruyère cheese.
  • Broil for 2-3 minutes until the cheese is melted, bubbly, and slightly browned.

6️⃣ Serve & Enjoy:

  • Garnish with fresh thyme.
  • Serve immediately and enjoy this warm, comforting dish!

Nutrition Facts (Per Serving)

  • 📊 Approximate Values
  • Calories: 420 kcal
  • Protein: 28g
  • Carbohydrates: 32g
  • Healthy Fats: 18g
  • Fiber: 3g
  • (Values may vary depending on ingredient substitutions and portion sizes.)

Recipe Notes & Pro Tips

  • Expert Tips for the Best Chicken French Onion Soup:
  • ✔ Caramelize the onions properly – This is the key to deep, rich flavor.
  • ✔ Use high-quality broth – Homemade or low-sodium beef broth works best.
  • ✔ Choose the right cheese – Gruyère is ideal for its nutty, melty texture.
  • ✔ Toast the bread well – Prevents sogginess when added to the soup.
  • ✔ Deglaze the pan with wine or brandy – Adds depth and complexity to the soup.

Storage & Reheating Instructions

    How to Store Leftovers:

    • Refrigeration: Store in an airtight container for up to 3–4 days.
    • Freezing: Freeze soup (without bread and cheese) in freezer-safe containers for up to 3 months.

    Best Ways to Reheat:

    • On the Stovetop: Warm over medium heat until hot.
    • In the Microwave: Heat in 1-minute intervals, stirring in between.
    • For the Topping: Toast bread and broil cheese fresh before serving.

    Frequently Asked Questions

    • 1️⃣ Can I Make This Soup Without Cheese?
    • Yes! For extra texture, serve with garlic-rubbed toasted bread instead.
    • 2️⃣ What’s the Best Slow Cooker Size?
    • A 6-quart slow cooker is ideal for this recipe.
    • 3️⃣ Can I Freeze This Soup?
    • Yes! Freeze without bread & cheese for up to 3 months.
    • 4️⃣ Is This Recipe Gluten-Free?
    • To make it gluten-free, use GF bread and ensure your broth is gluten-free.
    Keyword Slow cooker French onion soup