French Onion Chicken Macaroni and Cheese brings together everything you love about two ultimate comfort foods — the rich, caramelized flavor of French onion soup and the creamy goodness of baked mac and cheese. Tender chicken, golden onions, and a blend of Gruyère and mozzarella come together in every cozy, cheesy bite.
Why You’ll Love This Recipe
This dish is everything comfort food should be — cozy, creamy, and absolutely irresistible.
Here’s why you’ll love it:
- Made with simple pantry staples
- Ready in under an hour — perfect for busy nights
- Combines the deep flavor of caramelized onions with cheesy pasta
- Great way to use leftover rotisserie chicken
- Family-friendly and crowd-pleasing for any gathering
The first time I made this recipe on a cool autumn Sunday, the smell of caramelized onions filled the kitchen and brought everyone to the table — now it’s a must-make at every potluck and family dinner.
Ingredients
For the Caramelized Onions
- 2 medium yellow onions, diced
- 2 tablespoons olive oil
- 2 tablespoons unsalted butter
- 1 teaspoon sea salt
- ½ teaspoon black pepper
For the Mac and Cheese Base
- 16 oz elbow macaroni, cooked al dente and drained
- ½ cup (113 g) unsalted butter
- ½ cup (62.5 g) all-purpose flour
- 2 cups (490 g) warm whole milk
- 1 cup (240 g) beef stock
- 2 teaspoons kosher salt
- ½ teaspoon ground mustard powder
- ¼ teaspoon garlic powder
- ¼ teaspoon cayenne pepper (optional)
- 1 cup (113 g) shredded Gruyère cheese
- ½ cup (56.5 g) shredded mozzarella
- 2 cups (280 g) shredded rotisserie chicken
For the Topping
- Salt and pepper, to taste
- ¼ cup (28 g) shredded Gruyère cheese
- Fresh thyme, for garnish
Instructions
1. Preheat the Oven
Preheat to 350°F (175°C) and grease a 9×13-inch baking dish.
2. Caramelize the Onions
In a large skillet, melt olive oil and butter over medium-high heat. Add onions, salt, and pepper. Reduce the heat to low, cover, and cook for 25–30 minutes, stirring occasionally, until the onions are very soft.
Remove the lid, increase the heat to medium, and cook until the onions turn a deep golden brown. Set aside.
3. Make the Cheese Sauce
In a saucepan over medium heat, melt the butter. Whisk in the flour and cook for 1–2 minutes until fragrant and lightly golden.
Remove from heat, then slowly whisk in the warm milk and beef stock. Return to heat and cook for 3–5 minutes, whisking constantly, until thickened.
4. Season and Add Cheese
Whisk in kosher salt, mustard powder, garlic powder, and cayenne. Lower the heat and stir in Gruyère and mozzarella until melted and smooth. Fold in the caramelized onions.
5. Combine with Pasta and Chicken
In a large mixing bowl, combine the cooked pasta, cheese sauce, and shredded chicken. Mix until evenly coated, then transfer to the prepared baking dish.
6. Bake Until Golden
Top with extra Gruyère and bake uncovered for 12–15 minutes, or until bubbly and golden brown on top.
7. Garnish and Serve
Let rest for 5 minutes before serving. Sprinkle with fresh thyme and season with additional salt and pepper if desired.
Tips for Success
- Dice onions evenly so they caramelize uniformly.
- Always use freshly shredded cheese — it melts creamier and tastes richer.
- Let the dish rest before serving to allow the sauce to thicken slightly.
Substitutions & Variations
- Cheese Swap: Use Swiss or sharp white cheddar in place of Gruyère.
- Vegetarian: Skip the chicken and use vegetable stock.
- Gluten-Free: Substitute gluten-free pasta and 1:1 gluten-free flour.
- Extra Flavor: Add a splash of white wine while caramelizing the onions for a French bistro touch.
Storage Tips
Cool completely, then store in an airtight container in the refrigerator for up to 4 days. Reheat gently in the oven, covered with foil, or in the microwave with a splash of milk to refresh the sauce.
Serving Suggestions
Serve hot as a main dish with a crisp salad or roasted vegetables. It also pairs beautifully as a side with steak or roasted chicken. For extra flavor, top with more caramelized onions and thyme before serving.
A Little Culinary Inspiration
This dish is a love letter to French bistro cooking — inspired by classic French onion soup and transformed into an all-American baked macaroni favorite. The result? A hearty, golden casserole that’s every bit as indulgent as it is comforting.
Nutrition Information (Per Serving)
Approximate values only.
High in protein, calcium, and pure comfort — best enjoyed warm and shared with loved ones.