Flat Iron Steak Fajitas

By: Leigh Anne WilkesPosted: 9/12/22Updated: 5/11/23

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These Flat Iron Steak Fajitas are made with flat iron steak, peppers and onions and served on fresh flour tortillas. They are the best fajitas I have ever eaten!

What is Flat Iron Steak?

A flat iron steak is cut from the shoulder of the cow and is also called top blade steak or shoulder top blade steak. It is uniform in thickness and rectangular shaped. They are perfect for quick cooking methods and high heat so they are perfect for flat iron steak fajitas. This cut of meat is a tender and flavorful cut of meat.

Rub Ingredients Needed

paprika
brown sugar
cumin
chili powder
garlic powder
salt

Fajita Ingredients

Flat iron Steak. Can also use skirt steak or flank steak.
Oil. Use olive oil, vegetable or canola.
Lime juice
Bell Peppers. I like to use a combo of green, red, and yellow
Onion. Use a sweet or yellow onion.

How to Make Flat Iron Steak Fajitas

Mix together paprika, brown sugar, cumin, chili powder, garlic powder and salt.
Place steak in a large plastic resealable bag and add in juice of 1 lime, 1 Tbsp oil and the spice mixture. Rub the spices into the meat.
Refrigerate for 30 minutes to 2 hours.
In a cast iron skillet, add 1 Tbsp olive oil, onions and peppers. Cook over medium heat until the veggies are tender and the edges begin to char.
Cook meat in a cast iron pan or on the grill using the directions below until desired doneness.
Place sliced steak on tortilla with peppers and onions.
Garnish flat iron fajita with a little cilantro and grated cheese, pico or guacamole for the perfect flat iron steak fajita.

Grilled onions and peppers for Flat Iron Steak Fajitas

How to Cook Flat Iron Steak Fajitas in a Cast Iron Pan

Although grilling steak for flat iron steak fajitas works well I prefer to cook mine on the stove top in a cast iron pan.

Preheat your cast iron pan in a 400 degree F oven for about 20 minutes or heat it on high on top of the stove top for 4-5 minutes. You don’t want your cast iron to smoke, it is too hot if it is smoking.
Add a tablespoon or two of vegetable or canola oil to your hot pan and sear your flat iron steak for two minutes on each side over high heat.
Reduce the heat to medium and allow the steak to cook until a temperature of 125-130 degrees F is reached. Use a meat thermometer to check temperature. Cutting into the meat to see if it is done releases all the juices. I love using my Thermapen to check the temperature. Flip the meat every two minutes until desired temperature is reached.
Remove steak from pan to a cutting board and allow it to sit for five minutes with a piece of foil over it.
Slice the meat on a diagonal going across the grain.

How to Grill Flat Iron Steak Fajitas

Grill it over high heat, searing it on both sides for a couple of minutes and then reduce heat of grill or move steak off of direct heat and allow steak to cook until your desired temperature is reached.
A 125-130 degree F temperature is best. Don’t overcook! Allow steak to sit for five minutes off of the heat (it will continue to cook and come up to about 145 degrees F.), covered with foil and then slice into thin strips on the diagonal, going across the grain when ready to serve.

sliced steak for Flat Iron Steak Fajitas

Tips for Tender Fajitas

Don’t over cook. Fajitas are best when not cooked beyond medium (about 145 degrees F). Pull the meat off the grill when it heats about 135 degrees F and as it sits it will come up to temperature (145 degrees F) It gets tough if overcooked. Use a meat thermometer to check your temperature.

Marinade your meat. This cut of meat is best when marinated. A good marinade not only adds a ton of flavor, it should contain an acid like citrus, vinegar, or wine that helps tenderize the meat. Marinate the steak for a few hours before grilling to help tenderize the meat and give it lots of amazing flavor. If you are short on time, 30 minutes will do, but the longer the better.
Let your meat rest. After the meat is done cooking, cover with foil and allow to rest for about 10 minutes. The meat will continue to cook and this also allows the meat to absorb the juices so that when you cut into the meat all the juices don’t run out.
Slice thinly, against the grain. For the most tender meat be sure and cut the meat against the grain,

Frequently Asked Questions

What kind of tortillas should I use?

You can use a corn tortilla or a flour tortilla. If you are using flour, I prefer the ones you can buy that are uncooked. You usually find them in the deli section of the store. All you have to do is cook them up in a frying pan right before serving. They are so much better that way!!

What Can I Use instead of Flat Iron Steak?

You can use flank steak or skirt steak instead. All of these cuts of meat are best served grilled.

What do I put on a flat iron steak fajita?

After adding your meat and peppers and onions to the tortilla, you can also garnish with:
pico de gallo or salsa
avocados or guacamole
sour cream
cilantro
cheese