Chicken Fajita Casserole is a delicious and easy-to-make meal that brings all the bright, bold flavors of fajitas into a cozy, family-friendly dish. Imagine tender pieces of chicken mixed with lots of colorful bell peppers and onions, layered with gooey melted cheese and baked until bubbly and perfect. It’s like your favorite Tex-Mex dinner but made simple in one pan.
I love making this casserole on busy weeknights because it comes together quickly and still feels special. One of my favorite tips is to use fajita seasoning to get that authentic flavor without any extra effort. Plus, the leftovers taste just as good, so it’s great for packing lunches the next day. I usually toss everything together, pop it in the oven, and let the smell fill the kitchen — it’s such a comforting feeling.
When it’s time to eat, I like to top my portion with a dollop of sour cream and a sprinkle of fresh cilantro for a little fresh kick. Adding some warm tortillas on the side makes it feel like a proper fajita feast. This casserole always brings a smile to the table, and I bet it will in your home too!
Key Ingredients & Substitutions
Chicken: Using boneless skinless chicken breasts is perfect for even cooking and quick browning. You can swap for thighs if you prefer juicier meat; just adjust cooking time slightly.
Bell Peppers and Onions: These veggies add crisp sweetness and color. Red, yellow, or green peppers all work well, so pick your favorite or what you have on hand.
Fajita Seasoning: The seasoning mix is key to that classic fajita flavor. You can buy a packet or easily make your own with chili powder, cumin, paprika, garlic powder, and a pinch of cayenne.
Pasta: Cooked rotini or penne hold sauce well and give body to the casserole. For a lighter or gluten-free option, try whole wheat pasta or rice noodles.
Cheese: A Mexican blend usually includes cheddar and Monterey Jack for melt and mild flavor. If you prefer, mozzarella or pepper jack are great substitutes for creaminess or extra spice.
How Do I Cook the Chicken and Veggies Just Right for This Casserole?
Getting tender, flavorful chicken and perfectly softened veggies is important here. Follow these tips:
- Heat the pan and oil before adding chicken to get a nice sear.
- Cook chicken just until it’s mostly done; it will finish cooking in the oven, preventing dryness.
- Add sliced bell peppers and onions after the chicken has browned. Sauté about 5 minutes—just until they soften slightly but still keep some crunch and bright color.
- Stir in the fajita seasoning well so every bite is flavorful.
- Don’t overcook the veggies here; you want them to hold up in the casserole and not turn mushy.
Equipment You’ll Need
- Skillet – I like a large skillet for browning the chicken and sautéing the vegetables; it makes cooking everything easier and less dishes to wash.
- Mixing bowl – For tossing the cooked pasta, chicken, and veggies together before baking, so everything is evenly coated.
- 9×13-inch baking dish – The perfect size to hold your casserole while allowing it to bake evenly and get that bubbly cheese topping.
- Measuring spoons and cups – To measure your seasonings and ingredients precisely, ensuring the flavor is just right.
- Oven – For baking until the cheese melts and everything is heated through, creating that warm, cheesy finish.
Flavor Variations & Add-Ins
- Swap the chicken for cooked shrimp or ground beef to change the protein and try different flavors.
- Add in black beans or corn for extra texture and fiber; they work well with fajita seasonings and make the dish more filling.
- Mix in sliced jalapeños or a dash of hot sauce for some heat if you like spicy food.
- Use pepper jack cheese instead of Mexican blend for a bit of spice and extra meltiness.
Chicken Fajita Casserole
Ingredients You’ll Need:
Main Ingredients:
- 1 lb (450g) boneless skinless chicken breasts, thinly sliced
- 1 tbsp olive oil
- 1 packet (1 oz) fajita seasoning mix (or homemade blend)
- 1 large red bell pepper, thinly sliced
- 1 large yellow bell pepper, thinly sliced
- 1 medium onion, thinly sliced
- 3 cups cooked pasta (such as rotini or penne)
- 1 ½ cups shredded Mexican blend cheese (cheddar, Monterey Jack, etc.)
- ¼ cup chopped fresh cilantro, plus more for garnish
- 2 green onions, thinly sliced
Optional Garnishes:
- Sour cream
- Salsa
- Avocado slices
- Warm tortillas
How Much Time Will You Need?
This recipe takes about 15 minutes for preparation, 15-20 minutes to bake, and a few minutes to rest before serving. In total, plan for approximately 35-40 minutes from start to finish.
Step-by-Step Instructions:
1. Prepare and Cook the Chicken and Veggies:
Preheat your oven to 375°F (190°C) and lightly grease a 9×13-inch baking dish. Heat the olive oil in a large skillet over medium-high heat. Add the sliced chicken and cook it until it’s lightly browned but not fully cooked, about 4-5 minutes. Sprinkle the fajita seasoning over the chicken and stir to coat evenly. Add the sliced bell peppers and onion, cooking for another 5 minutes until the vegetables are slightly softened and the chicken is cooked through.
2. Mix Everything Together:
In a large bowl, toss together the cooked pasta, the chicken and vegetable mix, half of the shredded cheese, chopped cilantro, and green onions. Mix gently to combine all the ingredients.
3. Assemble and Bake the Casserole:
Transfer the mixture into your prepared baking dish. Sprinkle the remaining cheese evenly on top. Bake in the oven for 15-20 minutes, or until the cheese is melted, bubbly, and slightly golden.
4. Serve:
Remove the casserole from the oven and let it rest for a few minutes. Garnish with extra fresh cilantro. Serve warm with optional toppings like sour cream, salsa, avocado slices, and warm tortillas on the side for a complete meal.
Can I Use Frozen Chicken for This Casserole?
Yes, you can use frozen chicken, but be sure to thaw it completely before cooking. Thaw overnight in the fridge or use the defrost setting on your microwave to speed up the process. This helps ensure even cooking and better texture.
Can I Make This Casserole Ahead of Time?
Absolutely! Prepare the casserole up to the baking step, then cover it tightly and refrigerate for up to 24 hours. When ready to eat, bake as directed, adding a few extra minutes if baking straight from the fridge.
How Should I Store Leftovers?
Store any leftover casserole in an airtight container in the refrigerator for up to 3 days. Reheat in the oven at 350°F (175°C) until warmed through or microwave individual portions for convenience.
Can I Substitute the Pasta with Something Else?
Definitely! You can swap the pasta for cooked rice, quinoa, or even cauliflower rice for a low-carb option. Just make sure your substitute is cooked before mixing it into the casserole.
