When busy weeknights demand something more exciting than plain chicken and rice but you don’t have time for a full taco night spread, this Easy Chicken Fajita Casserole delivers the flavors you love in one simple, bake-and-forget dish. Tender strips of chicken, sautéed bell peppers and onions, all nestled in a creamy, cheesy sauce spiced with fajita seasoning—then baked until bubbly—this casserole captures the essence of fajitas without the skillet juggling or tortilla assembly.

I first developed this recipe on a hectic Monday when I wanted the bright, smoky notes of chicken fajitas but needed something I could prep in one bowl and pop into the oven. By browning the chicken with half the seasoning, then quickly softening the peppers and onions in the same pan, I concentrated those charred flavor bits before combining everything in a tangy sour-cream and cream-cheese base. A final layer of cheddar ensures each scoop is rich and melty. The result has become my go-to for feeding a crowd or stashing leftovers for easy lunches.

What makes this casserole particularly appealing is its flexibility. You can use breasts or thighs, adjust the peppers to whatever colors you have on hand, and swap the seasoning packet for a homemade blend if you prefer. Serve it over rice, alongside warm tortillas, or with crisp tortilla chips. Garnish with chopped green onions, fresh cilantro, or pickled jalapeños to dial up the freshness or the heat. Cleanup is minimal—just one skillet, one mixing bowl, and a casserole dish—making it perfect for both weeknights and casual gatherings.

In Part 1, we’ll cover the essential prep: heating the oven and dish, sautéing the chicken until lightly browned in fajita seasoning, and softening the peppers and onions. These foundational steps lock in that signature fajita flavor and set the stage for the creamy assembly in Part 2. Let’s get cooking.

STEPS

1. Preheat and prep
   Preheat your oven to 375°F (190°C). Lightly grease a 9×13-inch casserole dish with nonstick cooking spray or a thin coating of oil—this prevents sticking and helps the cheese crisp around the edges.
2. Sauté the chicken
   Heat 2 tablespoons of olive oil in a large skillet over medium-high heat until the oil shimmers. Add 1½ pounds of chicken breast or thigh strips, then sprinkle ½ packet of fajita seasoning evenly over the top. Cook without stirring for about 2 minutes to develop a light sear, then stir and continue cooking for another 3–4 minutes, until the chicken is just lightly browned on all sides but not fully cooked through. The goal is to lock in moisture and flavor—any residual cooking will finish in the oven. Transfer the chicken to a bowl and set aside, leaving the flavorful drippings in the pan.

1. Sauté the vegetables
   In the same skillet (no need to wash it), add the sliced bell peppers (one red, one yellow, one green) and one medium sliced onion. If needed, add a teaspoon of oil. Cook over medium heat for 4–5 minutes, stirring occasionally, until the vegetables are slightly tender but still retain a bit of crunch. Sprinkle the remaining ½ packet of fajita seasoning over the peppers and onions, toss to coat, and cook for an additional minute to bloom the spices. Remove from heat and add the chicken back to the pan, stirring just to combine—this ensures every piece of chicken and vegetable is infused with that smoky fajita flavor.

Easy Chicken Fajita Casserole: Creamy Assembly & Baking

Now that your chicken and peppers are perfectly seasoned and sautéed, it’s time to marry them with a tangy, creamy base, top with melty cheese, and bake until bubbly.

STEPS

4. Mix the creamy base
   In a large mixing bowl, combine 1 cup of sour cream and ½ cup of softened cream cheese. Stir with a spatula or whisk until smooth and uniform. Add the remaining fajita seasoning packet (or 2 tablespoons of your homemade blend) and fold in 1 cup of shredded cheddar or Mexican blend cheese until evenly distributed.

4. Combine chicken, veggies, and cream
   To the bowl with the creamy mixture, add the sautéed chicken strips and bell pepper–onion mixture. Stir gently to coat every piece in the cheesy sauce. Taste and adjust seasoning: add a pinch of salt, a crack of black pepper, or an extra dash of fajita spice if you like.

4. Assemble in the casserole dish
   Pour the chicken–cream–veggie mixture into the prepared 9×13-inch baking dish, spreading it into an even layer. Smooth the top with the back of a spoon or spatula so the cheese melts uniformly.
5. Top with cheese and bake
   Sprinkle the remaining 1 cup of shredded cheese over the surface. Slide the casserole into your preheated 375°F (190°C) oven and bake, uncovered, for 20–25 minutes—until the cheese is fully melted, golden at the edges, and the filling is bubbling.
6. Finish and garnish
   Remove the casserole from the oven and let it rest for 5 minutes. This short rest helps the sauce set slightly, making it easier to portion. If desired, garnish with chopped green onions, fresh cilantro, or sliced jalapeños for a pop of color and extra flavor.

TIPS & VARIATIONS

• Rice or grain base
  For a heartier casserole, line the bottom of the baking dish with 2 cups of cooked rice, quinoa, or cauliflower rice before adding the creamy chicken mixture.
• Veggie boost
  Fold in 1 cup of frozen corn kernels or black beans along with the chicken and peppers for added color, texture, and protein.
• Spice it up
  Stir ½ teaspoon of cayenne pepper or 1–2 chopped chipotle peppers in adobo into the creamy base for a smoky heat.
• Cheese swaps
  Use Monterey Jack for extra melt, pepper jack for spiciness, or a blend of smoked gouda and cheddar for depth.
• Make-ahead
  Prepare through Step 5 and refrigerate the assembled—but unbaked—casserole, covered, for up to 24 hours. When ready, top with cheese and bake as directed, adding 5 extra minutes if cold.
• Tortilla topping
  Scatter crushed tortilla chips or strips of corn tortillas on top of the cheese before baking for an extra crunchy finish.
• Slow-cooker method
  After sautéing chicken and veggies, transfer them to a 6-quart slow cooker. Stir in the creamy base, cover, and cook on LOW for 2–3 hours. Sprinkle cheese on top 15 minutes before serving and allow it to melt.
• Dairy-free adaptation
  Swap sour cream for dairy-free yogurt, use vegan cream cheese, and choose a plant-based shredded cheese to accommodate dietary needs.

With these steps and creative ideas, your Easy Chicken Fajita Casserole will become an effortless, crowd-pleasing weeknight staple—combining all the bold flavors of fajitas in a single, dreamy dish.

Easy Chicken Fajita Casserole: FAQs & Conclusion

Q1: Can I prepare this casserole ahead of time?
Yes. Assemble through Step 5 (combining chicken, veggies, and creamy base) and cover the dish tightly. Refrigerate for up to 24 hours, then top with cheese and bake at 375°F for an additional 5–10 minutes, or until heated through and bubbly.

Q2: How can I prevent the casserole from becoming watery?
Make sure to drain any excess liquid from the sautéed bell peppers and onions before mixing. If your sour cream or cream cheese is particularly loose, blot it with a paper towel or use a slightly firmer full-fat variety.

Q3: My cheese didn’t brown on top—what went wrong?
Every oven browns differently. For a golden top, switch the oven to broil for the last 1–2 minutes of baking. Watch closely to avoid burning.

Q4: What can I serve alongside this casserole?
This dish pairs beautifully with Mexican rice, warm flour or corn tortillas, a fresh green salad, or even tortilla chips for scooping. A dollop of guacamole or pico de gallo on the side adds brightness.

Q5: Can I make this dairy-free or vegan?
Yes. Substitute plant-based sour cream and cream cheese, and use a dairy-free shredded cheese. Confirm your fajita seasoning is vegan-friendly, or make your own blend of chili powder, cumin, garlic powder, and onion powder.

Q6: How should I store and reheat leftovers?
Cool the casserole to room temperature, then cover and refrigerate for up to four days. Reheat individual portions in the microwave or warm the entire dish in a 350°F oven for about 10–15 minutes, until heated through.

Q7: Is there a low-carb option?
Yes. Simply omit any rice base and serve the creamy fajita filling over cauliflower rice or a bed of shredded lettuce for a lighter, low-carb meal.

Conclusion

This Easy Chicken Fajita Casserole brings all the vibrant flavors of classic fajitas into one comforting, bake-and-serve dish. With layers of tender, seasoned chicken, sautéed peppers and onions, and a creamy, cheesy sauce, it’s an effortless way to satisfy fajita cravings without the fuss of tortillas or individual skillet servings. Whether you’re cooking for a crowd, feeding the family on a busy weeknight, or meal-prepping for the week ahead, this casserole adapts to your needs—offering make-ahead convenience, dietary swaps, and crowd-pleasing appeal. Gather your ingredients, follow these simple steps, and enjoy a delicious, stress-free twist on Tex-Mex at home.

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