Crock‑Pot French Onion Soup

Slow-cooked caramelized onions and flavorful broth combine in this French onion soup made in a crock‑pot. The long, gentle simmer builds sweetness and depth — finish with crusty bread and melty cheese on top for the ultimate cozy dish.

---

Why You’ll Love This Recipe

• Onions deeply caramelized and sweet from slow cooking
• Hands-off cooking — just set the crock-pot and let simmer
• Rich, savory broth that tastes complex and homemade
• Ideal comfort food that’s warm, filling, and satisfying
• Great for entertaining — double the recipe and serve in bowls

---

Ingredients You’ll Need

• 6 large yellow onions, thinly sliced
• 3 tbsp unsalted butter
• 1 tbsp olive oil
• 4 cups beef broth (or a mix of beef and chicken)
• 1 cup dry white wine (optional but adds depth)
• 1 tsp Worcestershire sauce
• 2 sprigs fresh thyme (or ½ tsp dried thyme)
• 2 bay leaves
• Salt & black pepper, to taste
• 4–6 slices baguette or crusty bread
• 1½ cups grated Gruyère cheese (or Swiss/Emmental)

---

Instructions

1. Caramelize Onions in the Crock-Pot
   • Add butter, olive oil, and sliced onions into the crock-pot.
   • Stir to coat the onions in butter and oil.
   • Cover and cook on low for 6–8 hours (or on high for 3–4 hours), stirring occasionally, until the onions are deeply golden and sweet.
2. Add Broth & Flavorings
   • Once the onions are caramelized, stir in beef broth, white wine (if using), Worcestershire sauce, thyme, and bay leaves.
   • Season with salt and pepper.
   • Cover and cook on low for another 1–2 hours, letting the flavors meld.
3. Prepare the Bread Topping
   • About 15 minutes before serving, preheat your oven broiler.
   • Place the baguette slices on a baking sheet and toast lightly under the broiler until golden on both sides.
   • Remove and set aside.
4. Finish & Serve
   • Ladle soup into oven-safe bowls or crocks.
   • Place a toasted baguette slice on top of each soup bowl.
   • Sprinkle a generous amount of grated Gruyère cheese over each bread slice.
   • Broil the bowls for 2–4 minutes, or until the cheese is melted, bubbly, and slightly browned.
   • Remove carefully (the bowls will be hot!) and serve immediately.

---

You Must Know

• Slow cooking helps develop sweetness and depth — don’t rush the caramelizing.
• Stir onions occasionally to prevent burning or sticking.
• Taste and adjust salt just before serving — flavors concentrate during long cooking.
• Use oven-safe bowls for finishing under the broiler or remove bread with cheese carefully if not.

---

Storage Tips

• Fridge: Store leftover soup (without bread topping) in an airtight container for up to 3 days.
• Reheat: Warm gently on the stove over medium heat. If too concentrated, add a splash of broth.
• Freezing: You can freeze the soup (without bread and cheese) for up to 2 months. Thaw and reheat gently.

---

Ingredient Substitutions

• Onions: Use a mix of yellow, white, and red onions for complex flavor.
• Broth: Use all chicken broth or vegetable broth if you prefer.
• Wine: Skip the wine and add more broth plus a splash of balsamic vinegar for acidity.
• Cheese: Use Swiss, Emmental, or mozzarella if Gruyère isn’t available.
• Bread: Use sourdough or ciabatta instead of baguette.

---

Serving Suggestions

• Serve with a crisp green salad and a glass of dry white wine.
• Pair with roasted meats or a cheese board for a cozy dinner.
• Enjoy as a starter or main course — plus, crusty bread is perfect for dipping.

---

Pro Tips

• Caramelize onions in batches if your crock-pot is too full — they’ll brown more evenly.
• If the soup is too sweet, add a splash of vinegar (white wine or balsamic) to balance.
• Remove thyme sprigs and bay leaves before serving to avoid biting into them.
• For a richer broth, stir in a tablespoon of butter or a splash of cream just before serving.

---

Frequently Asked Questions

→ Can I make this soup without wine?
Yes — just substitute with more broth and a little balsamic vinegar for richness.

→ How do I prevent onions from burning in the crock-pot?
Stir occasionally during cooking and cook on low rather than high for more controlled browning.

→ Can I cook this on the stove instead of using a crock-pot?
Definitely. Caramelize the onions in a Dutch oven over low heat (~45 minutes), then add broth and simmer before finishing with bread and cheese.

→ Is this recipe freezer-friendly?
Yes, you can freeze the soup (without bread and cheese) in a container for up to 2 months.

---

✨ This Crock‑Pot French Onion Soup is rich, slow-cooked, and deeply comforting — a homemade classic that warms you from the inside out.

Print