Flat Iron Steak Fajitas Recipe

Prepare marinade

Finely mince the garlic. In a medium bowl whisk together 2 tbs olive oil, 2 tbs fresh lime juice, minced garlic, 1 tsp ground cumin, 1 tsp smoked paprika, 1 tsp chili powder, 1 tsp black pepper, and 1/4 tsp salt until combined.

Marinate steak

Place the 1 lb flat iron steak in a shallow dish or zip-top bag. Pour marinade over the steak, massaging to coat both sides. Marinate in the refrigerator for at least 30 minutes and up to 4 hours. Remove from fridge 20 minutes before cooking to bring toward room temperature.

Preheat pan or grill

Heat a heavy skillet (cast iron preferred) or grill over medium-high heat until very hot, about 5 minutes. If using a skillet, add a thin film of oil (wipe excess if needed) so it smokes lightly.

Cook steak

Place the steak on the hot surface. Sear without moving for 3-4 minutes to develop a deep crust. Flip and cook another 3-4 minutes for medium-rare (internal temp ~130-135°F / 54-57°C). For medium, cook 1-2 minutes longer. Adjust time if steak is thicker or thinner.

Rest and slice

Transfer steak to a cutting board and tent loosely with foil. Rest for 8-10 minutes to allow juices to redistribute. Using a sharp knife, slice thinly across the grain into 1/4-inch strips for tender pieces.

Prepare vegetables

While the steak rests (or while it marinates), core and seed the bell peppers and slice into 1/4-inch strips. Peel the onion and cut into similar-width slices so they cook evenly.

Sauté vegetables

Heat a large skillet over medium-high heat. Add 1 tbs olive oil and swirl to coat. Add sliced onions and peppers in a single layer and cook, stirring occasionally, until softened and slightly charred at edges, about 6-8 minutes. Season with a pinch of salt and 1/4 tsp black pepper if desired. Remove from heat.

Combine with steak

Add the sliced steak to the skillet with vegetables and toss briefly to heat through and absorb juices, about 1 minute. Squeeze 1 tbs fresh lime juice over the mixture and stir. Taste and adjust seasoning if needed.

Warm low-carb tortillas in a dry skillet for 15-30 seconds per side or arrange large lettuce leaves. Divide the steak and pepper mixture among 8 tortillas or leaves.

Top each serving with a spoonful of low-sodium salsa, a few avocado slices if using, and sprinkle with chopped fresh cilantro. Serve with lime wedges on the side for extra brightness.

Leftovers: store steak and vegetables in an airtight container in the refrigerator for up to 3 days. Reheat gently in a skillet over low heat to avoid overcooking.