There are dinners that feel comforting the moment you pull them out of the oven, and this Chicken Fajita Casserole is absolutely one of them. Tender shredded chicken, sweet peppers and onions, and a creamy, cheesy sauce come together in the coziest way. It tastes like fajita night and casserole night decided to team up.
This is one of those recipes I make when I want big flavor without juggling a dozen pans. It is hearty, simple, and always a hit at the table. If you love easy keto dinners that feel generous and satisfying, you are going to love this one. Let's get cooking.
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Why You'll Love This Recipe
- Creamy, cheesy, and packed with fajita flavor
- Naturally keto and low carb
- Family-friendly and filling
- Great for make-ahead dinners
- Perfect for busy weeknights
- Tested many times to get the texture just right
Ingredients
- 10 boneless, skinless chicken thighs, about 2 pounds
- 1 red bell pepper, seeded and sliced into thin strips
- 1 large onion, peeled and sliced into thin strips
- 8 ounces cream cheese, softened
- 8 ounces shredded cheddar cheese
- 1 ½ tablespoons fajita seasoning
- Salt and black pepper, optional
Ingredient Notes and Substitutions
Chicken thighs: Thighs stay juicy and tender during baking. Chicken breasts work too, but keep a close eye so they do not dry out.
Peppers and onions: Letting them cook slowly brings out their natural sweetness. That soft, caramelized texture makes the casserole extra cozy.
Cream cheese: This forms the creamy base of the sauce. Make sure it is softened so it mixes easily.
Cheddar cheese: Sharp cheddar adds bold flavor, but a Mexican blend or Monterey Jack also works beautifully.
Fajita seasoning: Seasoning blends vary, so taste and adjust salt as needed once everything is mixed.
Instructions
- Preheat your oven to 350 F. Place the chicken thighs in a large casserole dish. Cover tightly with foil and bake for 30 to 35 minutes, until the chicken reaches 160 F.
- Remove from the oven and let cool for a few minutes. Shred or chop the chicken into bite-sized pieces. Drain any cooking liquid from the dish.
- While the chicken bakes, coat a skillet with cooking spray and cook the sliced pepper and onion over medium-low heat. Stir occasionally and let them soften and lightly caramelize. This usually takes about 25 to 30 minutes. Set aside to cool slightly.
- In a large bowl, mix the softened cream cheese, half of the shredded cheddar, and the fajita seasoning until smooth.
- Add the shredded chicken, cooked peppers, and onions. Stir until everything is evenly coated.
- Transfer the mixture back into the same casserole dish. Sprinkle the remaining cheese evenly over the top.
- Bake uncovered at 350 F for 25 to 30 minutes, until hot and bubbly.
- Let the casserole rest for a few minutes before serving so it sets nicely.
Pro Tips for Success
- Drain the chicken well to avoid extra moisture in the casserole.
- Let the peppers and onions cook slowly. That sweetness is worth the time.
- Taste the mixture before baking and adjust seasoning if needed.
- Letting it rest helps each scoop hold together beautifully.
Storage and Reheating
Store leftovers in an airtight container in the refrigerator for up to 3 days. Reheat gently in the oven or microwave until warmed through.
Make Ahead and Freezing
You can prepare the casserole through mixing and refrigerate it for up to 2 days before baking. If chilled, plan for a slightly longer bake time so it heats through evenly. Freezing works, but the texture is best fresh or refrigerated.
Tips and Variations
- Add sliced green bell peppers for more color
- Swap cheddar for pepper jack for extra heat
- Serve over cauliflower rice for a complete keto meal
- Top with avocado slices or sour cream before serving
- Turn leftovers into lettuce wraps the next day
FAQs
Yes, just be careful not to overcook them so they stay tender.
It is mild to medium, depending on your seasoning. You can adjust easily.
Absolutely. This recipe is perfect for make-ahead dinners.
📖 Recipe
Chicken Fajita Casserole
- Prep Time: 20 minutes
- Cook Time: 1 hour 10 minutes
- Total Time: 1 hour 30 minutes
- Yield: 8 servings 1x
- Category: dinner, Main Course
- Method: Bake
- Cuisine: American, Mexican
Description
Chicken Fajita Casserole has tender shredded chicken, onions, and peppers baked in a creamy cheese sauce. It's the best casserole ever-creamy, cheesy, and packed with flavor.
Ingredients
- 10 boneless skinless chicken thighs (about 2 pounds)
- 1 red pepper, seeded and sliced into small strips
- 1 large onion, peeled and sliced into small strips
- 8 oz cream cheese, softened
- 8 oz shredded cheddar cheese
- 1.5 tbsp fajita seasoning
- Salt & pepper (optional)
Instructions
- Preheat oven to 350°F.
- Place chicken thighs in a casserole dish, cover with foil, and bake until internal temperature reaches 160°F (about 30-35 minutes). Cool and shred or chop. Drain any liquid from dish.
- While chicken cooks, sauté onions and peppers in a frying pan over medium-low heat until golden and soft. Let cool slightly.
- In a large bowl, mix cream cheese, half the cheddar, and fajita seasoning. Add chopped chicken and cooked veggies, mix well.
- Transfer the mixture back into the casserole dish. Sprinkle with remaining cheddar.
- Bake uncovered at 350°F for 25-30 minutes until hot and bubbly.
Notes
- This casserole can be prepped ahead and refrigerated before the final bake. Add 10-15 minutes to bake time if chilled.
- Adjust salt depending on the sodium level of your fajita seasoning.
Nutrition
- Calories: 393.5
- Sugar: 2.8g
- Sodium: 394.4mg
- Fat: 25g
- Saturated Fat: 12.9g
- Trans Fat: 0.1g
- Carbohydrates: 4.5g
- Fiber: 0.8g
- Protein: 36.4g
- Cholesterol: 195.1mg
Serving Suggestions
This Chicken Fajita Casserole is wonderful on its own, but I love adding fresh toppings like avocado, sour cream, or a sprinkle of cilantro. It also pairs well with a simple green salad for a balanced dinner.
Nutrition and Notes
- Servings: 8
- Calories: about 394 per serving
- Net carbs: about 3.7g per serving
This is one of those casseroles that disappears fast in my house. It is warm, creamy, and full of flavor without feeling heavy.
Reader Reviews
"This was incredible. Creamy, flavorful, and so easy to make. Even the leftovers were amazing."
Related Recipes and Internal Links
If you enjoy easy keto casseroles, try my Keto Taco Casserole for another weeknight favorite.
You may also love my Slow Cooker Crack Chicken when you want hands-off comfort food.
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