Cheesy Chicken Fajita Casserole

The first time I made this casserole, it was supposed to be regular fajitas for a Tuesday night dinner. But it had been one of those chaotic work days where standing at the stove flipping individual tortillas felt like asking too much. I threw everything in a baking dish instead, and my husband actually asked if we could have it this way every time.

My sister was over that first experimental night, skeptical about baking fajitas instead of cooking them in a cast iron skillet. When she took her first bite and went back for seconds without saying a word, I knew I had stumbled onto something good. Now its her most requested dish whenever she visits.

Ingredients

• 3 cups cooked chicken breast: Rotisserie chicken works perfectly here, or use leftovers from a roasted chicken
• 3 bell peppers (red, green, yellow): Using all three colors makes it visually stunning and adds slight flavor variations
• 1 large onion, sliced: Sweet onions work beautifully, but any variety will do the job
• 2 cups shredded Mexican blend cheese: The pre-shredded mix saves time, but shredding your own melts better
• 1/2 cup sour cream: Full fat gives the best texture and richness
• 4 oz cream cheese, softened: Let it sit out while you prep everything else so it incorporates smoothly
• 1 can diced tomatoes with green chilies: Drain well so your casserole doesnt become watery
• Chili powder, cumin, smoked paprika, garlic powder, onion powder: This spice blend creates that classic fajita seasoning profile
• 1/4 tsp cayenne pepper: Skip this if youre sensitive to heat
• 1 tbsp olive oil: For sautéing the vegetables until theyre perfectly softened
• Fresh cilantro and green onions: These bright garnishes make a huge difference in the final presentation

Instructions

Get your oven ready:

Preheat to 375°F and grease a 9x13-inch baking dish with butter or cooking spray.

Sauté the vegetables:

Heat olive oil in a large skillet over medium-high heat, add the sliced peppers and onions, and cook for 6 to 8 minutes until theyre soft and starting to caramelize at the edges.

Mix everything together:

In a large bowl, combine the chicken, sautéed vegetables, drained tomatoes, all the spices, softened cream cheese, and sour cream. Mix thoroughly and season with salt and pepper.

Assemble the casserole:

Spread the mixture evenly in your prepared dish and cover the top with the shredded Mexican cheese.

Bake until bubbly:

Bake uncovered for 25 to 30 minutes until the cheese is golden and you can see the sauce bubbling up around the edges.

Let it rest and serve:

Wait 5 minutes before serving, then sprinkle with fresh cilantro and green onions if you like.

Save

This became our go-to dish when friends had babies or were going through tough times. Its easy to transport, serves a crowd, and somehow manages to taste even better when its made with love for someone else.

Make It Your Own

Ive tried swapping the chicken for shredded turkey after Thanksgiving, and honestly, it might be even better. The darker meat adds so much flavor. You could also use steak or leave the meat out entirely and add black beans for a vegetarian version that still feels substantial.

Serving Ideas

Warm flour tortillas on the side are non-negotiable in my house. The contrast between the creamy casserole and soft, warm tortillas is absolute perfection. A simple green salad with lime dressing cuts through the richness nicely, and Spanish rice makes it feel like a complete Tex-Mex feast.

Prep Ahead

You can assemble the entire casserole up to 24 hours before baking, which makes it perfect for busy weeknights or entertaining. Just cover it tightly and refrigerate, then add about 10 extra minutes to the baking time since it will be cold going into the oven.

• Freeze unbaked casseroles for up to 3 months, thaw overnight in the refrigerator before baking
• The vegetables can be sliced and the chicken shredded a day or two in advance
• Double the recipe and make two—one for now, one for the freezer

Save

Theres something so satisfying about a dish that takes familiar flavors we all love and transforms them into something new and convenient. This casserole has saved more weeknights than I can count.

Recipe FAQs

→ Can I use rotisserie chicken?

Yes, rotisserie chicken works perfectly and saves time. Simply shred about 3 cups from a store-bought rotisserie chicken and proceed with the recipe as written.

→ How do I store leftovers?

Store cooled leftovers in an airtight container in the refrigerator for up to 4 days. Reheat in the microwave or oven at 350°F until heated through.

→ Can I make this ahead?

Absolutely. Assemble the complete casserole, cover tightly, and refrigerate for up to 24 hours before baking. You may need to add 5-10 extra minutes to the baking time.

→ What can I serve with this?

Warm flour or corn tortillas, Mexican rice, refried beans, or a simple green salad with lime vinaigrette all make excellent sides.

→ How can I make it spicier?

Add diced jalapeños with the peppers, increase the cayenne to 1/2 teaspoon, or use pepper jack cheese in place of some Mexican blend.

→ Can I freeze this casserole?

Yes, freeze before baking. Wrap the assembled dish tightly in plastic and foil for up to 3 months. Thaw overnight in the refrigerator before baking.