Flank Steak Fajitas

Tender, juicy, and flavorful flank steak fajitas with peppers and onions that you can cook on the grill or in a skillet on the stovetop!

Course Dinner

Cuisine Mexican

Keyword flank steak fajitas, grilled steak fajitas, steak fajitas recipe

Prep Time 10

Cook Time 30

Total Time 40

Servings people

Calories 329.8kcal

Author Blair Lonergan

2 lbs. flank steak (or sub with skirt steak)
1 large onion, thinly sliced
2 sweet bell peppers (any color), thinly sliced
Olive oil
Optional, for serving: salsa, flour tortillas, sour cream, guacamole, shredded cheese, fresh lime juice, cilantro

In a small bowl, stir together the seasoning.
Rub the seasoning into the beef and set aside. Reserve any leftover seasoning for the vegetables, if desired.

Prepare a hot fire by piling charcoal on one side of grill, leaving other side empty. (For gas grills, only light one side.) Place food grate on grill. Place steak on lit side of grill. Grill, covered with grill lid, over medium-high heat (350° to 400°) about 20 minutes, flipping halfway through. If you are cooking a smaller flank steak or skirt steak (about 1 lb.), it may only need about 15 minutes on the grill.
The steak is done when the edges are charred and crispy, and you see some nicely dark searing on the top. Check the temperature in the thickest part with an instant-read thermometer: 115 to 120°F for rare steak, 120 to 125°F for medium-rare steak, 130 to 135°F for medium steak, and 140 to 145°F for medium-well steak.
Let the steak rest while you prepare the vegetables.

Heat a large cast iron pan or griddle over high heat. Add 1 tablespoon of oil to the hot skillet and heat the oil for 1 more minute. Sear the steak in the hot oil for about 3-4 minutes per side, or until it reaches desired temperature.
Check the temperature in the thickest part with an instant-read thermometer: 115 to 120°F for rare steak, 120 to 125°F for medium-rare steak, 130 to 135°F for medium steak, and 140 to 145°F for medium-well steak.
Let the steak rest while you prepare the vegetables.

Heat 2 tablespoons of oil in a cast iron skillet over medium-high heat. Cook and stir the onions and peppers in the hot oil until they’re tender (about 7-10 minutes). Season with salt and pepper, to taste.

Warm up the tortillas by heating them in the microwave, on the grill or in a dry pan.
Slice the beef against the grain in ½-inch thick slices. Serve the beef with the warm tortillas and the vegetables. Garnish with optional toppings and serve!

This steak fajita seasoning has a small amount of "heat," thanks to a little bit of cayenne. I would consider it comparable to "medium" salsa. If your family prefers a spicier fajita, increase the amount of cayenne or serve the fajitas topped with jalapeños. By contrast, if you want a more mild fajita seasoning, I suggest cutting the amount of cayenne in half (or omit it altogether).

Cooking time will vary depending on the size, thickness, and cut of your meat, as well as your personal preference. It's always best to use a digital instant-read meat thermometer to know when your steak has reached the ideal temperature.

Thinly slice the meat against the grain (perpendicular to those natural lines that you see running through the steak). This shortens the muscle fibers and tenderizes the meat.

We prefer soft, warm flour tortillas with fajitas, but you can also serve the meat and veggies with corn tortillas, over rice, on cauliflower rice, or on top of salad.

Warm the tortillas in the microwave wrapped in damp paper towels until heated through, about 15-30 seconds. You can also char or toast flour or corn tortillas directly on gas burners over a medium-low flame for about 15 seconds per side.

Squeeze fresh lime juice over the fajitas just before serving for a bright, acidic finish.