Flank steak fajitas are something we don’t eat enough. I’ve seriously been making fajitas since I was 12 years old, yet we somehow replaced the fajita with the fish taco craze the past few years. With a cast iron skillet, you can make everything in one pan and it will stay nice and hot when serving—just like a restaurant.
Cast iron skillet fajitas are partly inspired by a new side dish I dreamt up a few months ago. Sauteed poblano peppers and red onions. It’s the perfect flavorful topping over brown rice or quinoa. Don’t know how we arrived there, but who doesn’t love grilled peppers and onions in fajitas?
Poblano peppers have a lot more flavor than your typical bell pepper. They have a hint of smoke and spice, yet overall are very mild. Paired with red onions and seasoned flank (or skirt) steak, it’s all you need for a perfect fajita—plus maybe a little cheese and avocado!
Flank Steak Fajita Marinade
Most people marinade flank/skirt steak, however, for simplicity, I opted for a homemade dry rub consisting of chili powder, cumin, paprika, garlic, and brown sugar. It adds a nice spicy, flavorful touch with a hint of citrus (from fresh lime) and brown sugar.
If you prefer an overnight marinade, I’ve used the following basic marinade with solid results. You can easily make your own with a blend of oil, spices, and acids. Let rest for 24 hours for most flavor-infused results. Overnight or 6 hours works too.
Basic carne asada marinade:
- 1/4 cup soy sauce
- 1/4 cup olive oil
- 2 limes, juice squeezed
- 2 garlic cloves, sliced
- 1 teaspoon cumin
- 1 teaspoon paprika
- salt and pepper, to taste
How to Cut Flank Steak
One critical tip when serving steak fajitas is to properly (and thinly) slice the steak for tenderness (I learned the hard way). Skirt and flank steak tend to be very flavorful, yet tougher cuts due to the dense muscle fibers. You will notice the steak has a very defined grain running through it. It may be more noticeable after you cook it. Slicing strips with the grain will force you to bite through these tough fibers. If you slice against the grain, the meat will break apart much easier.
No one likes fajitas that fight back.
Poblano peppers, red onions and medium-rare flank steak rubbed with a spicy blend of Mexican spices. Top with cheese and avocado.
- 1 pound flank or skirt steak
- 3 poblano peppers, sliced
- 1 medium red onion, sliced
- 10–12 6-inch flour tortillas
- 1–2 avocados, sliced, for topping
- 2 limes
- Mexican blend cheese, for topping
- Fresh cilantro, for topping
- 2 tablespoons canola oil, for searing
- 1 teaspoon chili powder
- 1 teaspoon cumin
- 1 packed teaspoon, brown sugar
- 1/2 teaspoon paprika
- 1/2 teaspoon garlic powder
- Pinch of salt and pepper to taste
- Remove steak from the fridge 30 minutes before searing. Combine all steak seasoning ingredients in a small bowl and mix well. Coat both sides of the steak in juice from half a lime, rubbing into the meat. Dry rub each side of the steak with a heaping teaspoon of steak seasoning, fully coating. Let rest for 30 minutes.
- Meanwhile, thinly slice the poblano peppers and red onion, set aside.
- Add 1 tablespoon of oil to a cast iron skillet and turn up to medium-high heat. Allow the skillet to become hot first. Place the steak face down and sear undisturbed for 4-5 minutes. Flip and sear for an additional 4-5 minutes. Remove from the pan and place on a plate. Cover in aluminum foil.
- Add the peppers and onions to the skillet with another tablespoon of oil, reduce heat to medium and cook until tender and golden, about 5-7 minutes. Season with salt and pepper.
- Place the steak on a cutting board and find the natural grain running lengthwise through the steak. Cut the steak into thin slices AGAINST the grain. This is to ensure the steak is tender and easy to bite. If you slice with the grain, the meat will be much tougher to bite.
- Return the steak to the skillet and sear longer on the stove top if desired (for medium and higher).
- Serve directly in the skillet with warm tortillas, sliced avocado, cheese, and lime wedges.
Cooking steaks at high temps in a skillet tends to get smokey. Open a kitchen window and turn on your kitchen’s overhead vent fan before you start to help with ventilation.
Temperatures for steak
Rare: 120° F to 125° F
Medium rare: 125° F to 130° F
Medium: 135° F to 140° F
Medium well: 145° F to 150° F
Well done: 160° F and above
Keywords: flank steak fajitas, skillet fajitas