Chicken with French Onion Flavor Baked in a Bubbly Casserole 🍗🧅🥘

Why You’ll Love This French Onion Chicken Casserole

✅ One-pan convenience – Less mess, more flavor
✅ Deep, savory flavor from caramelized onions and beef broth
✅ Melty cheese topping makes it irresistible
✅ Great for weeknights or guests – fancy flavor with little effort
✅ Low-carb & high-protein – fits a variety of lifestyles

Ingredients You’ll Need

For the Casserole Base:

• 4 boneless, skinless chicken breasts (or thighs)

• 1 tablespoon olive oil

• 2 large yellow onions, thinly sliced

• 2 tablespoons butter

• 1 teaspoon sugar (to help caramelize)

• 1 cup beef broth (low-sodium recommended)

• 1 tablespoon Worcestershire sauce

• ½ teaspoon garlic powder

• ½ teaspoon thyme (fresh or dried)

• Salt & black pepper, to taste

For the Topping:

• 1 ½ cups shredded mozzarella cheese

• ½ cup grated Parmesan cheese

• Optional: Fresh parsley for garnish

How to Make French Onion Chicken Casserole

Step 1: Caramelize the Onions

1. Heat butter and olive oil in a skillet over medium-low heat.

2. Add the sliced onions and sugar.

3. Cook for 25–30 minutes, stirring often, until the onions are soft, golden, and sweetly caramelized.

🔥 Pro Tip: Don’t rush the onions – low and slow is key for deep flavor!

Step 2: Sear the Chicken

1. While the onions are cooking, season your chicken breasts with salt, pepper, and garlic powder.

2. In another skillet (or the same one if you remove the onions), sear the chicken on both sides until golden – about 3–4 minutes per side. It doesn’t need to be fully cooked yet.

Step 3: Assemble the Casserole

1. Preheat your oven to 375°F (190°C).

2. In a 9x13-inch baking dish, spread half of the caramelized onions on the bottom.

3. Lay the seared chicken breasts on top.

4. In a small bowl, mix beef broth, Worcestershire sauce, and thyme, then pour it over the chicken.

5. Top with remaining onions, then sprinkle mozzarella and Parmesan cheeses evenly over everything.

Step 4: Bake It

• Cover the dish with foil and bake for 25 minutes.

• Remove the foil and bake an additional 10–15 minutes, or until the cheese is bubbling and golden and chicken reaches 165°F internal temperature.

Optional Add-Ins & Variations

🧄 Add garlic – sauté 2 cloves with the onions for more flavor
🍄 Add mushrooms – cook with the onions for a French onion mushroom chicken twist
🥔 Make it a full meal – layer sliced cooked potatoes under the chicken
🍷 Add a splash of white wine – into the broth mix for elegance
🧀 Try Gruyère cheese – for a classic French onion flavor

What to Serve With It

This casserole pairs wonderfully with:

• Mashed potatoes or creamy cauliflower mash

• Buttered green beans or roasted broccoli

• Buttered egg noodles or wild rice

• Crusty French bread to soak up all the bubbling sauce

• Simple side salad with a tangy vinaigrette

Storing & Reheating

Refrigerator: Store leftovers in an airtight container for up to 4 days.

Freezer: This dish freezes well! Freeze individual portions in airtight containers for up to 2 months.

Reheating: Reheat in the microwave or oven at 350°F until hot and bubbly.

Nutritional Info (Per Serving – Approx. 4 servings)

• Calories: ~420

• Protein: 40g

• Fat: 24g

• Carbohydrates: 8g

• Sugar: 3g

• Sodium: ~600mg

Nutritional values will vary depending on cheese and broth used.

Frequently Asked Questions

Can I use chicken thighs instead of breasts?
Absolutely! Thighs stay juicy and flavorful, and they work great here.

Is this casserole low-carb or keto?
Yes, it’s naturally low in carbs and perfect for keto with just a few net carbs per serving.

Can I make this in advance?
Yes! Assemble the casserole up to a day ahead, cover, refrigerate, and bake when ready.

What if I don’t have beef broth?
You can use chicken broth, but beef broth gives that signature “French onion” depth.

Final Thoughts

If you're craving something cozy, cheesy, and packed with deep, savory flavor, this Chicken with French Onion Flavor Baked in a Bubbly Casserole is your answer. It brings together the best parts of comfort food – rich flavor, hearty ingredients, and a cheesy top layer – all in one easy-to-make dish.

Perfect for family dinners, date nights, or even meal prep, this casserole is guaranteed to win hearts and fill bellies.