French Onion Chicken Soup is a cozy twist on the classic French onion soup, replacing the traditional beef broth with tender chicken and keeping all the rich, caramelized onion goodness. You get those sweet, deeply cooked onions swimming in a savory, hearty chicken broth, topped with melty cheese and crusty bread. It’s warm and comforting, perfect for chilly days when you want something that feels like a big, tasty hug in a bowl.
I love making this soup because it’s such an easy way to mix up traditional flavors with a lighter twist. The caramelized onions take some time but are so worth it—they add a sweet depth that makes the soup taste fancy even when it’s just a weekday meal. I usually stir in some thyme and a splash of sherry or white wine whenever I have it on hand, which gives it a little something extra without complicating the recipe.
One of my favorite ways to serve this is right out of individual oven-safe bowls, topped with a thick slice of toasted baguette and a generous layer of melted Gruyere or mozzarella. Watching the cheese bubble and brown under the broiler is always a highlight! It’s the kind of meal that brings everyone to the table and gets everyone talking about seconds.
Key Ingredients & Substitutions
Yellow Onions: These are best for caramelizing because they become sweet and soft. If you can’t find yellow, sweet onions or even white onions work pretty well, just adjust cooking time accordingly.
Chicken Breasts: I like boneless, skinless for easy cooking and shredding if you want. You could swap for thighs for juicier meat or use rotisserie chicken to save time.
White Wine: This adds a bit of acidity and depth. If you avoid alcohol, chicken broth or a splash of apple cider vinegar is a good substitute.
Gruyère Cheese: It melts beautifully and has a mild nutty flavor. Swiss cheese, mozzarella, or even provolone can work if you can’t find Gruyère.
Bread: Crusty baguette slices are classic. You can also use sourdough or ciabatta. Toasting helps avoid sogginess under the cheese.
How Do I Get Perfectly Caramelized Onions Without Burning Them?
Slow and steady is the key! Patience will turn your onions rich and sweet.
- Cook sliced onions on medium-low heat with butter and a little oil to prevent sticking.
- Stir often, but not constantly. Let them sit a bit between stirs to brown.
- Add sugar halfway through to help caramelization, but watch closely so it doesn’t burn.
- If they stick or brown too fast, lower the heat and add a splash of water or broth to loosen.
- This process takes about 30-40 minutes—don’t rush it!
Caramelized onions create the base flavor, so taking your time here really pays off with a deep, rich soup.
Equipment You’ll Need
- Large heavy-bottomed pot or Dutch oven – perfect for browning chicken and slowly caramelizing onions without burning.
- Wooden spoon or heat-safe spatula – helps stir onions gently and scrape up browned bits.
- Sharp chef’s knife – makes slicing those onions thin and even easy.
- Baking-safe soup bowls or ramekins – for broiling the cheesy topping right before serving.
- Broiler or oven – melts and browns the cheese on top perfectly.
Flavor Variations & Add-Ins
- Use chicken thighs instead of breasts for juicier, more flavorful meat that stays tender.
- Add sliced mushrooms with the onions for extra earthiness and texture.
- Swap Gruyère for mozzarella or provolone cheese if you want a milder, gooey melt.
- Stir in fresh thyme or rosemary for extra herbal notes whenever you like.
How to Make French Onion Chicken Soup?
Ingredients You’ll Need:
For The Soup:
- 4 boneless, skinless chicken breasts
- Salt and freshly ground black pepper, to taste
- 2 tablespoons olive oil
- 4 large yellow onions, thinly sliced
- 3 cloves garlic, minced
- 1 tablespoon unsalted butter
- 1 teaspoon sugar
- ¼ cup dry white wine (optional)
- 6 cups chicken broth (preferably low sodium)
- 2 teaspoons fresh thyme leaves (or 1 teaspoon dried thyme)
- 1 bay leaf
For The Topping:
- 4 slices French baguette or crusty bread
- 1 ½ cups grated Gruyère or Swiss cheese
- Fresh parsley, chopped, for garnish
How Much Time Will You Need?
This recipe takes about 15 minutes to prepare, 30-40 minutes to caramelize the onions, plus 15-20 minutes to simmer the soup with chicken. Toasting and broiling with cheese adds another 10 minutes. Overall, plan for about 1 hour and 10 minutes from start to finish.
Step-by-Step Instructions:
1. Searing the Chicken:
Season both sides of the chicken breasts with salt and pepper. Heat olive oil in a large pot or Dutch oven over medium-high heat. Sear the chicken for 3-4 minutes on each side until golden brown but not fully cooked through. Remove the chicken and set it aside.
2. Caramelizing the Onions:
Lower the heat to medium and add butter to the same pot. Add the thinly sliced onions and stir to coat them in butter and oil. Cook the onions, stirring frequently, for about 30-40 minutes until they are richly caramelized and golden. Halfway through, sprinkle the sugar over the onions to help with caramelization.
3. Building the Soup:
Add the minced garlic to the pot and stir for about a minute until fragrant. If using, pour in the white wine and scrape up any browned bits from the bottom. Let it reduce for 2-3 minutes. Then, add the chicken broth, fresh thyme, and bay leaf. Bring to a gentle simmer.
4. Cooking the Chicken in the Soup:
Return the seared chicken breasts into the pot. Cover and let simmer on low for 15-20 minutes, or until the chicken is fully cooked and tender.
5. Preparing the Toppings:
While the soup gently simmers, preheat your broiler. Toast the baguette slices until golden and crisp.
6. Assembling and Broiling:
Take the chicken breasts out of the soup and ladle some of the caramelized onion broth into oven-safe bowls. Place a chicken breast in each bowl and spoon extra onions and broth over. Top each chicken breast with a toasted baguette slice, then generously sprinkle with grated Gruyère cheese.
7. Final Touch:
Place the bowls under the broiler for 3-5 minutes until the cheese melts and bubbles beautifully. Garnish with chopped fresh parsley and serve immediately for a warm, comforting meal.
Can I Use Frozen Chicken for This Soup?
Yes, but make sure to fully thaw the chicken breasts before cooking. Thaw them overnight in the refrigerator or use the cold water method by sealing the chicken in a bag and submerging it in cold water for quicker thawing. This helps ensure even cooking and food safety.
Can I Make This Soup Ahead of Time?
Absolutely! You can caramelize the onions and prepare the broth a day early. Store the soup and cooked chicken separately in the fridge for up to 2 days. Reheat gently on the stove before assembling and broiling the cheese topping fresh.
How Should I Store Leftovers?
Keep leftovers in airtight containers in the refrigerator for up to 3 days. To reheat, warm the soup on the stove over medium heat until heated through, then add the toasted bread and cheese and briefly broil or microwave to melt the cheese.
What Can I Use Instead of Gruyère Cheese?
If you don’t have Gruyère, Swiss cheese is the closest substitute for flavor and meltiness. Mozzarella or provolone work too and give a milder, gooey topping. Avoid very strong cheeses that might overpower the delicate onion broth.
