In a bowl, combine sliced steak with olive oil, lime juice, chili powder, cumin, garlic powder, salt, and pepper. Mix well and let it marinate for 15–20 minutes. This helps tenderize the meat and infuse it with classic fajita flavors.

Heat a skillet over medium-high heat and cook the steak in a single layer for 2–3 minutes per side until browned and just cooked through. Remove from the pan and set aside. In the same skillet, sauté the bell peppers and onions for about 4–5 minutes until slightly softened but still crisp.

Place a tortilla in a clean skillet over medium heat. Sprinkle a layer of cheese, then add cooked steak and vegetables, followed by more cheese. Top with another tortilla or fold in half, pressing gently. Cook until the bottom is golden and crispy.

Flip the quesadilla and cook the other side until crispy and the cheese is fully melted. Remove from the pan, let it rest for a minute, then slice into wedges and serve warm.