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These Easy Steak Fajitas are juicy, tender, flavorful, and way better than the ones at your favorite Mexican restaurant! Served with a healthy dose of peppers and onions, these fajitas are gluten-free, low carb, and paleo.

Cooked Steak Fajitas with Onions and Peppers in a Black Cast Iron Pan

Steak fajitas are one of my favorite easy Mexican dinners of all time. They’re great for summer grilling, perfect for celebrations like Cinco de Mayo, and make a wonderful addition to your weekly meal prep routine.

They’re incredibly versatile. You can serve them as tacos with guacamole and sour cream, as an entree with Mexican rice and refried beans, or as a low-carb lunch with an avocado salad and cilantro lime cauliflower rice.

Steak fajita marinade ingredients in small white bowls and ziplock bag with marinating flank steak.

The secret to flavorful steak fajitas

The secret to getting the meat irresistibly flavorful and juicy is marinating the steak for at least 2 hours up to 8 hours.

This helps tenderize the meat and infuse all the good flavors that are in the actual marinade. I know the marinating process requires planning, but the end result is so worth it.

Once finished, remove the meat from the marinade and place it on a surface covered with paper towels. Pat the steak until completely dry and generously season with coarse sea salt and crushed black pepper.

Pro tip: Using coarse sea salt is very important. It helps to further tenderize and break down the fibers of the meat, making the steak super juicy and melt-in-your-mouth delicious.

Sliced steak fajitas in warm flour tortillas with peppers and onions.

What kind of beef do you use for fajitas?

Flank steak and skirt steak are the best cuts of beef for fajitas. I prefer to use flank steak (pictured above). Whichever cut of beef you use, make sure to cut it as thinly as possible to prevent it from being too chewy.

How to cook steak fajitas

To cook the flank or skirt steak, heat a large skillet or grill pan over medium-high heat. Coat the skillet or grill with a bit of oil and cook each side of the steak for about 3-5 minutes, depending on how thick it is.

My husband is a master at using the finger test to check for doneness, whereas I prefer to use a meat thermometer.

This is the meat thermometer that I have, and I use it all the time.
They’re inexpensive and take all the guesswork out of knowing whether something has reached a certain temperature or not.

Peppers and onions in a black cast iron skillet with steak fajitas.
    4.65 from 111 votes

    Easy Steak Fajitas

    Juicy, tender, and flavorful steak fajitas served with peppers and onions that are better than your favorite Mexican restaurant!
    Prep: 2 hours 30 minutes
    Cook: 25 minutes
    Total: 2 hours 55 minutes
    Servings: 8 servings
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    Ingredients 

    For the meat and marinade

    For the pepper and onions

    • 2 ยฝ tablespoons cooking oil, divided
    • 2 medium white onions, sliced
    • 1 large poblano pepper, sliced into strips
    • 3 large bell peppers, sliced into strips
    • 1 pinch kosher salt

    Optional toppings

    • guacamole, sour cream, cilantro, flour tortillas, corn tortillas, lettuce cups

    Instructions 

    • In a large resealable plastic bag (or a large mixing bowl) add all the ingredients except the coarse sea salt and black pepper and toss to combine. 
    • Cover and marinate in the fridge for 2 hours up to 8 hours. 
    • Remove the meat from the marinade, transfer to a clean large surface or cutting board and pat dry with paper towels. Generously season both sides of the steak with coarse sea salt and black pepper.
    • In a large skillet over medium-high heat, add 1 tablespoon of cooking oil. Add the steak to the skillet and cook on each side for about 3-5 minutes, depending on how thick the steak is and how “done” you want it to be. I recommend using a meat thermometer for this step if you have one.
    • Remove the steak from the skillet, transfer to a cutting board to let it rest and lightly cover with aluminum foil. 
    • While the meat is resting, add the remaining 1 1/2 tablespoons of cooking oil to the skillet. Add the onions, peppers and a pinch of salt. Cook, stirring occasionally, for about 8 minutes, until the veggies are soft. 
    • Uncover the steak and slice it against the grain and at an angle into thin slices. Serve along with the fajita veggies in tortillas, on a salad or in lettuce cups and enjoy!

    Notes

    Use coarse sea salt after marinating the steak to help further tenderize and break down the fibers of the meat.
    Cut your steak against the grain and as thinly as possibly to prevent it from being chewy.
    If you’re looking to add a little more flavor to the peppers and onions, you could reserve a tablespoon or two of the marinade before you use it for the meat, and add it to the skillet when you’re ready to cook the veggies.

    Nutrition

    Serving: 1/8th of recipe | Calories: 262kcal | Carbohydrates: 9g | Protein: 25g | Fat: 14g | Saturated Fat: 5g | Polyunsaturated Fat: 3g | Monounsaturated Fat: 2g | Trans Fat: 0g | Cholesterol: 75mg | Sodium: 681mg | Potassium: 216mg | Fiber: 2g | Sugar: 5g | Vitamin A: 1150IU | Vitamin C: 109.7mg | Calcium: 30mg | Iron: 2.9mg

    Nutrition information is automatically calculated, so should only be used as an approximation.

    Did you make this recipe?Leave a comment and star rating below!

    Update Notes: This recipe was originally posted in 2018, but was updated in April of 2019 with new photos and tips.

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    69 Comments

    1. george says:

      isabel, i have read your recipes before, all great!!!
      i add all kinds of peppers to my fajitas (except the really hot ones)…
      i prefer plain old yellow onions…i like the taste…
      i use more expensive cuts of meat, new york, filet, t-bone, or rib eye…
      your marinade sounds great!!!! i will try it…thank you…

    2. Tina says:

      Can I make the marinade the night before, but add the steak for 2 hours the next day? If not mine would have to marinate for about 10.5 hours.

      1. Isabel says:

        Yes! You can make the marinade beforehand and then just add the steak in the next day. That’s totally a-okay! I hope you like it!

    3. Donn says:

      Yup!!

    4. DW says:

      5 stars
      Yup!!

    5. Leslie says:

      5 stars
      Oh my…these are amazing. I changed up to using part of my recipe for the rest of the filling. I used a flank steak and cooked it 3 mins on each side in my cast iron skillet on high. Fabulous. Cut it against the grain, mixed it in with my cooked onions, cheese, taco sauce. Rolled them into soft tacos, cheese on top and into the oven at 350 for about 15 mins. The steak is the key because of this fabulous marinade. Thank you so much !!!!

      1. Isabel says:

        Oh my goodness, Leslie. Your soft tacos with cheese on top sound amazing!! What a great way to serve them! So glad you liked the recipe!

    6. Gwen Clemens says:

      5 stars
      I have a question before I make it. how many people does it feed

      1. Isabel says:

        8 servings.

    7. Kathy Corso says:

      5 stars
      My husband and I made these fajitas and they were delicious!! No need to go out a Mexican restaurant. We will make this recipe again when my daughter and son in law come over.

    8. Macy says:

      What would you suggest doing with the tortillas? Just warm them up in the oven or something else?

      1. Ana @ Isabel Eats says:

        Hello Macy! We suggest warming up your torillas on a comal if you have one, or another tip is to place your tortillas inside a ziplock bag, add a splash of water and leave the bag with a slight opening and heating them up the microwave. Hope this helps!

    9. Kristin says:

      Hi, Isabel!

      I know cilantro is authentic Mexican, but I’m one of the 13% of the population for whom cilantro tastes like soap. Ick! Is there another seasoning you recommend that would also be good to replace the cilantro, or do you think I should just leave it out and be done?

      Thanks!

      1. Isabel says:

        You could use parsley instead. If you don’t like parsley, you can just leave it out.

    10. Dalia says:

      5 stars
      I loveddd it

      1. Isabel says:

        Thank you so much! So happy you liked it!

        1. Chantal says:

          Have you ever prepared the steak meat to freeze for a later quick meal?
          If so, how did you do it?

        2. Ana @ Isabel Eats says:

          Hi Chanal! We recommend freezing the steak when it is seasoned but still raw.