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A beautifully set dining table featuring a bowl of rich, steaming French onion soup. The golden, bubbly cheese stretches as a spoon lifts a bite, revealing layers of flavors beneath. A side of crispy Keto Air Fryer Chicken Breast and a fresh Carnivore Chicken Salad are plated beside the soup for a complete and satisfying meal.

Crockpot French Onion Soup Recipe

This Crockpot French Onion Soup is slow-cooked to perfection, with deeply caramelized onions, rich beef broth, and a golden, cheesy crust. A cozy, restaurant-quality dish made effortlessly at home!
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Prep Time 30 minutes
Cook Time 4 hours 45 minutes
Total Time 5 hours 15 minutes
Course Soup
Cuisine French
Servings 8
Calories 442 kcal

Equipment

  • Slow cooker (Crockpot)
  • Large skillet (for initial onion caramelization)
  • Cutting board & knife
  • Wooden spoon
  • Ladle
  • Oven-safe bowls
  • Baking sheet (for toasting bread & melting cheese)

Ingredients
  

  • 6 tablespoons butter
  • 4 large yellow onions sliced and separated into rings
  • 1 tablespoon white sugar
  • 2 cloves garlic minced
  • ½ cup cooking sherry
  • 7 cups reduced-sodium beef broth
  • 1 teaspoon sea salt or to taste
  • ¼ teaspoon dried thyme
  • 1 bay leaf
  • 8 slices of French bread
  • ½ cup shredded Gruyere cheese
  • ⅓ cup shredded Emmental cheese
  • ¼ cup freshly shredded Parmesan cheese
  • 2 tablespoons shredded mozzarella cheese

Instructions
 

  • Melt butter in a skillet, add sliced onions, and cook until golden brown (about 20 minutes). Stir in sugar and garlic.
    A close-up shot of a black cast-iron skillet on a rustic wooden countertop, filled with thinly sliced yellow onions slowly caramelizing in melted butter. The onions glisten as they turn a deep golden brown, while a wooden spoon stirs them gently. Soft wisps of steam rise from the pan, enhancing the warm, savory aroma.
  • Transfer onions to the slow cooker. Add sherry, beef broth, salt, thyme, and bay leaf. Cook on low for 6-8 hours or high for 3-4 hours.
    A close-up shot of a black slow cooker on a white marble countertop, filled with deeply caramelized onions. A steady stream of cooking sherry is being poured in, followed by rich beef broth, fresh thyme sprigs, and a single bay leaf floating on top. The ingredients come together to create a flavorful, aromatic base for the soup.
  • Remove the bay leaf and stir well.
    A wide-angle shot of the slow cooker covered with a glass lid as the French onion soup simmers gently for several hours. Soft steam fogs up the inside of the lid, showing the rich, golden broth infused with deep caramelized flavors.
  • Toast the French bread slices in the oven until crisp.
    A close-up shot of a rustic wooden tray holding several slices of golden-brown toasted French bread. The bread has a perfectly crispy crust with a soft, airy interior, ready to be placed on the soup for the final broiled topping.
  • Ladle soup into oven-safe bowls, top each with a toasted bread slice, and sprinkle with Gruyère, Emmental, Parmesan, and mozzarella cheese.
  • Place the bowls under the broiler for 2-3 minutes until the cheese is bubbly and golden.
  • Let it cool slightly, then serve hot.
  • Enjoy the rich, cheesy goodness with a side of Keto Air Fryer Chicken Breast or a Protein-Packed Carnivore Chicken Salad.
    A beautifully set dining table featuring a bowl of rich, steaming French onion soup. The golden, bubbly cheese stretches as a spoon lifts a bite, revealing layers of flavors beneath. A side of crispy Keto Air Fryer Chicken Breast and a fresh Carnivore Chicken Salad are plated beside the soup for a complete and satisfying meal.