Start by mixing the lime juice, olive oil, garlic, cumin, chili powder, black pepper, and a pinch of cayenne in a small bowl. Stir everything until fully combined. This zesty marinade will tenderize the steak while infusing it with flavor.

Place the steak in a large resealable plastic bag and pour the marinade over it. Ensure the steak is completely coated by massaging the marinade into it. Seal the bag and refrigerate for a minimum of 1 hour or up to 4 hours. Avoid marinating longer to prevent the lime juice from breaking down the meat too much.

Heat a large skillet or grill pan over medium-high heat. Sear the steak for about 3-4 minutes per side, depending on your preferred doneness (135°F for medium-rare). Once done, remove it from the pan and allow it to rest for at least 5 minutes. Resting locks in the juices, keeping the meat tender and flavorful.

While the steak is resting, add the sliced onions and bell peppers to the same pan. Sauté them over medium-high heat for 4-5 minutes until they’re tender and slightly charred. This step adds a sweet, smoky flavor to your fajitas.

Once rested, slice the steak into thin strips against the grain. Cutting this way ensures each bite is tender and easy to chew.

Add the sliced steak back into the skillet with the vegetables and toss everything together. This blends the flavors beautifully and keeps the fajitas warm.