Cheesy Chicken Fajita Casserole

The first time I made this casserole, it was supposed to be fajitas for a Tuesday night dinner, but I was running late and everyone was already hungry. I threw everything into a baking dish instead, and my husband actually said it was better than the original version. Now it's become one of those recipes I can make without even thinking, the kind that makes the whole house smell incredible.

Last winter, my sister came over with her kids after a chaotic day of Christmas shopping, and I needed something that felt like comfort food but wasn't another heavy pasta dish. This casserole came to the rescue, and even her picky five-year-old went back for seconds, which might be the highest compliment I've ever received on a recipe.

Ingredients

• 3 cups cooked chicken breast: Rotisserie chicken works perfectly here and saves so much time on busy weeknights
• 1 large red bell pepper: The sweetness of red peppers balances the spices beautifully
• 1 large green bell pepper: Adds that classic fajita flavor and gorgeous color contrast
• 1 large yellow bell pepper: I always grab whatever three colors look freshest at the store
• 1 large onion: Sweet onions caramelize best but yellow onions work perfectly fine
• 2 cups shredded Mexican blend cheese: Pepper jack adds a nice kick if your family enjoys some heat
• 1/2 cup sour cream: Full fat creates the creamiest texture, but reduced fat works too
• 4 oz cream cheese: Let it sit on the counter for 30 minutes so it blends smoothly
• 1 can (10 oz) diced tomatoes with green chilies: Rotel is my go-to brand, but store brands work well
• 1 tsp chili powder: I like to use ancho chili powder for deeper, smokier flavor
• 1 tsp ground cumin: Toast the cumin briefly in a dry pan before adding for extra fragrance
• 1/2 tsp smoked paprika: This is the secret ingredient that makes it taste restaurant-quality
• 1/2 tsp garlic powder: Fresh garlic can burn in the oven, so powder works better here
• 1/2 tsp onion powder: Rounds out the seasoning blend perfectly
• 1/4 tsp cayenne pepper: Leave it out for kids or double it if you love spice
• Salt and black pepper: Taste before baking since the cheese and tomatoes add saltiness
• 1 tbsp olive oil: Helps the vegetables caramelize rather than steam
• Fresh cilantro: The bright, fresh flavor cuts through all that rich cheese
• Sliced green onions: Add these right before serving so they stay crisp and colorful

Instructions

Preheat your oven:

Get it to 375°F and grab your favorite 9x13 baking dish. I give it a quick spray with cooking spray even if it's nonstick.

Sauté the vegetables:

Heat that olive oil in your biggest skillet until it shimmers. Toss in all those sliced peppers and onions, cooking them until they're soft and starting to brown in spots, about 8 minutes.

Mix everything together:

In a large bowl, combine your chicken, those gorgeous sautéed vegetables, diced tomatoes, and all those spices. Add the softened cream cheese and sour cream, mixing until everything is coated and creamy.

Assemble the casserole:

Spread the mixture into your prepared baking dish, then scatter that Mexican cheese over the top like you're tucking it in for a nap.

Bake until bubbly:

Slide it into the oven for 25 to 30 minutes. You'll know it's done when the cheese is perfectly golden and you can see the sauce bubbling up around the edges.

Let it rest and garnish:

Wait 5 minutes before serving, which feels impossible but helps the pieces hold together better. Sprinkle with fresh cilantro and green onions right at the table.

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This dish has become my go-to for new neighbors and families with new babies because it travels well and reheats beautifully. Last month, I brought it to a friend who just had her third baby, and she texted me the next day asking for the recipe because her husband couldn't stop talking about it.

Make Ahead Magic

I often assemble this casserole the night before, cover it tightly with foil, and keep it in the refrigerator. Just add 5 to 10 minutes to the baking time if it's going into the oven cold from the fridge. You can also freeze it unbaked for up to three months, then thaw overnight in the refrigerator before baking.

Serving Suggestions

Warm flour tortillas on the side turn this into an interactive meal, letting everyone make their own fajita-style wraps. Sometimes I serve it over cilantro-lime rice for a more substantial dinner, or with a simple green salad dressed with lime vinaigrette to cut through the richness.

Customization Ideas

Leftover cooked steak or even ground beef work beautifully in place of the chicken. For a low-carb version, skip the tortillas and serve over cauliflower rice. Black beans, corn, or diced jalapeños can be stirred in before baking for extra texture and flavor.

• Try Monterey Jack cheese instead of Mexican blend for a milder flavor
• Add a layer of crushed tortilla chips on top for extra crunch
• Mix in a can of black beans for more protein and fiber

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There's something so satisfying about a recipe that takes familiar flavors and makes them even better in a new form. This casserole has earned its permanent spot in my regular dinner rotation, and I bet it'll find its way into yours too.

Recipe FAQs

→ Can I make this casserole ahead of time?

Yes, you can assemble the entire casserole up to 24 hours in advance and refrigerate it before baking. Add 5-10 minutes to the baking time if baking cold from the refrigerator.

→ What's the best way to shred the chicken?

Use two forks to pull apart cooked chicken breasts, or place the cooked chicken in a stand mixer with the paddle attachment and mix on low for 30-60 seconds for perfectly shredded meat.

→ Can I freeze this casserole?

Yes, assemble the casserole and wrap tightly before freezing for up to 3 months. Thaw overnight in the refrigerator before baking as directed, or bake from frozen adding 20-25 minutes to the cooking time.

→ What vegetables work well in this dish?

Beyond the classic bell peppers and onions, you can add sliced mushrooms, zucchini, or corn. For a lower-carb version, replace some peppers with cauliflower or broccoli.

→ How can I make it spicier?

Add diced jalapeños with the vegetables, increase the cayenne pepper to 1 teaspoon, or use pepper jack cheese instead of Mexican blend. You can also serve with hot sauce on the side.

→ What should I serve with this casserole?

Warm flour tortillas, Spanish rice, refried beans, or a simple green salad with lime dressing all pair beautifully. You can also serve with tortilla chips and guacamole for a complete Tex-Mex spread.