This Baked Fajita Chicken Casserole is an easy one-pan recipe. My version is made with boneless, skinless chicken thighs, bell peppers, mushrooms, onions and cheese. Perfect to serve over rice, cauliflower rice or gluten-free pasta, this cheesy chicken fajita bake can be ready in less than 45 minutes.
❤️ Why you'll love this recipe
- When you're looking for a quick weeknight meal that will keep everyone around the table happy, look no further! This gluten-free Easy Cheesy Baked
Fajita Chicken Casserole is something your whole family will like.
- Made with juicy chicken thighs, colourful bell peppers, onions and mushrooms and topped with cheese, this casserole is all made in one pan.
- This healthy chicken fajita bake is made without cream cheese.
- Easy to make and easy to clean up! Great for busy weeknights.
Chicken fajitas are a favourite of mine and I make them year-round. I like the convenience of these Air Fryer Chicken Fajitas. They make a quick meal to stuff in tortillas.
This Chicken Fajita Bowl with Cauliflower Rice makes a great low-carb dinner, full of all those spicy Mexican flavours we love.
In the summer, these Chicken Fajitas in Foil Packets are an ideal choice for camping, picnics or outdoor barbecues. Super convenient to make ahead!
🛒 Ingredients and substitutions
You'll find a complete list of ingredients with amounts in the recipe card below. But before we get to the full recipe, here are a few notes about the ingredients.
- chicken: I like to use boneless, skinless chicken thighs in this recipe. They stay juicy and it's hard to overcook them. You can also use boneless, skinless chicken breasts if you prefer. Just check that you don't overcook them as they can become dried out.
- bell peppers: any colour, but green bell peppers are not as sweet as red, yellow or orange. Using a variety of colours makes this chicken fajita dinner even more appetizing!
- onion: Onions add a rich umami flavour and even a bit of natural sweetness. If you like you can add red onion for a sweet, yet tangy flavour.
- garlic: You'll need a clove of fresh garlic. You can substitute garlic powder in a pinch.
- fajita seasoning: use homemade fajita/taco seasoning mix or see the list of seasonings in the recipe card below.
- cheese: Choose a cheese that melts well. Monterey Jack or Pepper Jack or a combination of one of these with cheddar cheese works well in this cheesy chicken fajita bake.
- oil: like olive oil, grapeseed or avocado oil for sautéing the vegetables.
- toppings: your choice! Offer sliced avocado or guacamole, pickled jalapeños, salsa or pico de gallo, sour cream, fresh parsley or cilantro, and lime wedges for squeezing on the finished dish.
🔪 How to make baked fajita chicken casserole
Here's an overview of what you'll do to make this recipe perfectly. You'll find complete instructions in the recipe card at the end of this post.
You'll start by sautéing onions, peppers, mushrooms and garlic in a large oven-proof skillet. Next you'll remove these veggies from the pan and brown the fajita-seasoned chicken pieces. You'll add the sautéed veggies back into the skillet, sprinkle with grated cheese and bake! That's it.
- Prepare the vegetables and aromatics. Grate the cheese.
- Cut the chicken into bite-sized pieces. Coat with fajita seasoning.
- Sauté the onions, peppers and mushrooms. When the onions become translucent, add the minced garlic and cook for another minute or two.
- Transfer the veggies from the pan to a bowl. In the same skillet, brown the chicken pieces.
- Add the sautéd vegetables back into the skillet.
- Top with grated cheese and bake in the oven.
🔁 Possible Variations
Stir in a cup of drained and rinsed black beans before adding the cheese. You can also add a couple of generous handfuls of baby spinach at the same time.
👍🏼 Helpful Tips
Once the chicken casserole is baked, there will be juices from the chicken and the mushrooms left in the pan. Don't drain it off. It's absolutely delicious when you serve this baked fajita chicken with rice or pasta.
Many recipes for chicken fajita casseroles simply bake raw chicken and raw peppers and onions together with cheese in a baking dish. I've found that this method doesn't have as much flavour if you don't brown the chicken first. It can also be tricky to have both the chicken and the veggies cooked perfectly when you're baking them all at the same time.
If you don't have a skillet that can go in the oven, sauté the veggies and brown the chicken in the skillet according to the recipe instructions. Then transfer the mixture to a 9 x 13-inch casserole dish, top with grated cheese and bake it in the oven.
Yes, this is a good recipe for meal prep.
Prepare the casserole up to the point where you would normally transfer it to the oven. Instead, transfer it to a baking dish, cover and refrigerate.
When you're ready to bake, let it come to room temperature, then bake as directed. Always check to make sure the chicken has reached an internal temperature of 165°F.
I like to use a large 12-inch cast iron pan to cook this fajita casserole, but any large oven-proof skillet will work.
You'll also need an instant-read thermometer to check the temperature of the cooked chicken. It should register 165°F. to be safe to eat.
🍽 Serving Suggestions
Serve this baked fajita chicken dish over cooked white or brown rice, or over al dente gluten-free pasta. You can also use it to fill taco shells or tortillas!
Offer your favourite toppings! It's fun to load up your plate with choices, like
- sliced avocado
- salsa or pico de gallo
- sour cream
- pickled jalapeño peppers
- halved cherry tomatoes
- chopped fresh cilantro or parsley
- tortilla chips
⏰ Storage Instructions
To store: Refrigerate leftovers promptly and store them in a covered container for 3 days. Use the leftovers in a tortilla for lunch the following day.
To reheat: Reheat in the oven at 350°F. for 15 - 20 minutes or until heated through, or gently reheat it in the microwave.
Freeze it: Freeze in an airtight container for up to 3 months.
🗒 More easy casserole recipes to try
- Salsa Verde Chicken Tortilla Casserole
- Cheesy Tomato Gnocchi Bake
- Mini Vegetarian Shepherd's Pie with Mushrooms
- Vegetarian Pot Pie with Puff Pastry
- Seafood Pot Pie with Puff Pastry
🗒 More chicken recipes
When you make this cheesy chicken fajita casserole recipe, please leave a comment and a star rating below. I love hearing from you! Thanks in advance. Subscribe to my newsletter and receive new recipes delivered straight to your inbox once a week.
Baked Fajita Chicken Casserole
- 2 tablespoons olive oil
- 1 medium onion
- 2 large bell peppers, red, orange or yellow
- 4 ounces mushrooms
- 1 clove garlic
- 1.5 pounds boneless, skinless chicken thighs
- 2 tablespoons fajita seasoning mix* see below
- 2 cups grated cheese, a combination of Cheddar and Jack cheese, like Monterey Jack or Pepper Jack.
- 1 tablespoon fresh parsley or cilantro, chopped
- optional toppings: sliced avocado, sour cream, pico de gallo, guacamole, chopped tomato
- Preheat your oven to 375°F.
- Prepare the vegetables and aromatics (onions and garlic). Slice the onion, peppers and mushrooms, mince the garlic, and grate the cheese.
- Cut the chicken thighs into bite-sized pieces. Sprinkle all over with fajita seasoning.
- Heat oil in a large oven-proof skillet over medium heat. Add the onions, peppers and mushrooms and sauté until the onions are translucent and the peppers have softened, 4 to 5 minutes.
- Add the minced garlic to the skillet and cook for another minute or two, stirring to distribute it evenly.
- Transfer the vegetables and aromatics to a bowl.
- Add the chicken pieces to the hot skillet. Brown the chicken on all sides for about 5 minutes.
- Add the vegetables and aromatics back into the skillet on top of the chicken.
- Sprinkle with grated cheese.
- Bake for 15 minutes or until cheese has melted and the internal temperature of the chicken is at least 165°F.
- Remove from the oven, sprinkle with chopped parsley or cilantro and add optional toppings.
- 6 tablespoon chili powder
- 2 tablespoon cumin
- 2 tablespoon garlic powder
- 2 tablespoon paprika
- 1 tablespoon dried oregano
- 1 tablespoon onion powder
- 2 teaspoon salt
- 2 teaspoon pepper
- 2 teaspoon crushed red pepper flakes