Name: Easy Chicken Fajita Casserole Recipe
Prep time: 15 min
Cook time: 30 min
Total time: 45 min
Yield: 4 servings
Cuisine: Mexican
Ingredients: 2 large chicken breasts, sliced into strips; 1 red bell pepper, sliced; 1 yellow bell pepper, sliced; 1 green bell pepper, sliced; 1 medium onion, thinly sliced; 2 tablespoons olive oil; 2 teaspoons fajita seasoning; 1 cup shredded cheddar cheese; 1 cup shredded Monterey Jack cheese; Salt and pepper to taste

So, Here’s Why I Keep Making This Easy Chicken Fajita Casserole

I have this weird habit of making casseroles when the weather’s acting up, kind of like how some people bake bread when it rains. One Saturday (I think it was last October?), I was staring at a pack of chicken breasts and a mountain of peppers—honestly, why do I buy peppers in bulk?—when it hit me to mash up fajitas and casserole. And, wow, it’s become my lazy weeknight lifesaver ever since. It’s like getting the cool sizzle of fajitas but without standing over a hot pan for ages. Plus, and this is secretly my favorite part, you stick it in the oven and catch up on an episode of something. Once, I missed the timer because I got sucked into that TV show about people rescuing donkeys (don’t ask, long story…)

Why You’ll Love This (Not Just Because I Say So)

I make this when I’m short on time, out of energy, or, to be honest, when the fridge situation is dodgy but I’ve still got the basics. My family goes absolutely bonkers for it more than any other chicken recipe (especially if I remember to buy those tiny little corn tortillas—that’s all my son wants, with cheese on the side). I used to get frazzled juggling the skillet and the oven for regular fajitas, but with this casserole… well, now I can sit down for five minutes before dinner. If you’ve ever overcooked chicken by accident (me, repeatedly), this method is so forgiving. Also, there’s plenty of cheese. Did I mention that? That helps anything.

What You’ll Need (Plus Some Flexible Swaps)

2 large chicken breasts, thinly sliced (but thighs work fine—honestly, I think they’re juicier, but my partner disagrees, so take that as you will)
3 bell peppers, mixed colors, sliced (
red is sweetest but green’s cheaper, so I just buy what looks good)
1 big onion, sliced (I use yellow; my grandmother swore by sweet onions though)
2 tsp fajita seasoning, or taco seasoning in a pinch—I make my own sometimes but the packet kind from the latino aisle is fine
3/4 cup sour cream, or Greek yogurt if you’re being virtuous
1 can (10 oz) diced tomatoes with green chilies, like Rotel (plain diced works, but you’ll miss a bit of zing)
1 1/2 cups shredded cheese, Mexican blend is my go-to, but cheddar or Monterey Jack is totally fine (I sometimes go halfsies if I’m out)
1 tbsp olive oil
Salt and pepper, a good 1/2 tsp each or just wing it like I do half the time
A handful of chopped cilantro (optional—I know some people say it tastes like soap, no judgment)

How To Make It (and Where I Usually Sneak a Taste)

Preheat your oven to 375°F (190°C). Unless you, like me, forget sometimes—then just stick it in when you remember.
Drizzle olive oil in a big skillet (or kinda deep pan) and toss in your sliced chicken, sprinkle a pinch of salt and pepper. Cook just until it turns white, about 3-4 minutes—it’ll finish cooking in the oven, so don’t stress.
This is where it gets fun: dump peppers and onions into the same skillet (no need to clean it, that’s flavor), and sauté everything for another 3-5 minutes. If it starts sticking, add a tiny splash of water.
Stir in your fajita seasoning and the canned tomatoes (juice and all). Simmer for a minute. This is when I usually sneak a taste and adjust spice—sometimes more salt; sometimes hot sauce.
In a big bowl (or seriously, just use the skillet if it’s oven-safe—less dishes!), stir together the chicken mixture and half the cheese. Then mix in the sour cream. It’ll look a bit gloopy—don’t worry, it sorts itself out.
Pour the whole party into a greased 9×13 casserole dish. Sprinkle the rest of the cheese on top. Sometimes I go overboard here—no regrets.
Bake uncovered for about 20–25 minutes, or until the cheese is gooey and a bit golden xaround the edges. If you start picking off burnt cheese, you’re doing it right.
Let it cool for 5 minutes. Not longer, because it smells too good. Scatter chopped cilantro, if you’re feeling fancy.

Stuff I Wish I’d Known Sooner…

If you try to mix everything together really fast, you’ll probably spatter cheese everywhere. I learned the hard way. Take your time—it’s supposed to be fun.
I actually think it tastes better the next day, cold out of the fridge (don’t tell my family I pick at the leftovers for breakfast).
If it comes out a bit watery, you probably used the whole tomato can juice. No big deal; just use a slotted spoon when serving.

If You Want to Tweak It—Here’s What Worked (and Didn’t)

With Rice: I tried mixing in a cup of cooked rice once right before baking. It became super hearty, but kinda dried out unless I added more sour cream.
Spicy Version: Add chopped jalapeños or a squirt of chipotle paste. My kids weren’t fans, but I loved it. Maybe too much.
Vegetarian Attempt: Swapped the chicken for canned black beans. Nice flavor, but kinda mushy. Honestly, not the best, but still edible if you’re desperate.
I once tried putting tortilla chips under everything. Got soggy. Wouldn’t do that again.

What If I Don’t Have a Skillet (or Anything Fancy)?

No worries at all—I’ve used just a normal saucepan before; it takes a few extra stirs, but works fine. Someone once asked if you could make it in a slow cooker—probably, but I’d use less liquid and lots more cheese to avoid a soggy mess.

Storing What’s Left (if There Is Any)

I read somewhere that you should store it in an airtight container in the fridge for up to 3 days. In my house, it rarely lasts more than a day; people nibble at it for midnight snacks, so I’m honestly not sure how long you could save it. If you ever want to freeze it, wrap portions individually—maybe add a tiny splash of broth when reheating since the microwave dries things up fast.

How We Serve It (And a Little Family Quirk)

Oh, we’re all over the map here. Some nights, it’s scooped over rice (especially if I made Mexican rice like this one), or just piled into flour tortillas with extra cheese and hot sauce. Once in a blue moon, I do up a side of homemade refried beans and nobody talks for five minutes at the table. My aunt always puts lime wedges out for squeezing over, which just gets everything a little more zippy.

Stuff I’ve Learned (By Messing Up More Than Once)

Don’t rush the oven step! I once pulled it early and the cheese wasn’t even melted—won’t do that again.
Resist the urge to dump in extra sour cream at the end. It gets soupy. On second thought, maybe just a bit on top instead.
Let it cool just a bit before trying to slice—unless you want a lava flow (I almost always do anyway…)

Some Burning Questions (I Really Get These!)

Can I use pre-cooked chicken?: Totally! Just skip the first skillet step and toss it with the seasonings and veggies. Leftover rotisserie chicken is a winner.
What if I don’t have fajita mix?: Pinch of chili powder, cumin, garlic powder, and some paprika—anything southwest-ish. I’ve winged it many times.
Can I double it for a crowd?: Yes, but honestly, get a huge casserole dish or two. My oven struggles with super tall casseroles—sometimes it stays cold in the middle. Just saying.
Is it gluten-free?: Should be, as long as whatever seasoning you use is gluten-free—always worth a double-check. And don’t forget: be careful with the tortillas on the side if that matters.
Do I have to use sour cream?: Nope. Greek yogurt, or even crème fraîche (my friend Lisa does that, fancier than me!).

And that’s it. Go on, give it a whirl. It’s one of those dishes that gets easier every time, and if you completely mess up? Hey, that’s what extra cheese is for.