In a large bowl, whisk together the lime juice, minced garlic, chopped cilantro, cumin, chili powder, salt, and pepper to make the fajita marinade
Add the flank steak to the marinade and toss to coat. Cover the bowl with plastic wrap or foil and refrigerate for at least 30 minutes
While the steak is marinating, slice the bell peppers and onion into thin strips
Heat olive oil in a large skillet over medium-high heat. Add the sliced peppers and onions to the skillet, along with salt and pepper to taste
Cook for about 10 minutes until vegetables are tender-crisp. Remove from skillet
Remove flank steak from marinade (discard remaining marinade); pat dry it using a paper towel, then season both sides generously with salt & pepper
In the same skillet used for veggies, cook flank steak for about 6 -8 minutes per side or until cooked according to preference
Let rest on the cutting board for about five minutes before slicing thinly against grain (this will give you more tender pieces)
Assemble your fajitas by placing some of the cooked vegetables onto each tortilla, followed by slices of beef, then garnish with additional cilantro if desired
Enjoy this delicious recipe that will become a family favorite!