Prepare the Steak: Season the sirloin steak with olive oil, salt, and pepper. Heat a skillet over medium-high heat and sear the steak for about 4-5 minutes on each side, or until it reaches your desired doneness. Remove from heat and let it rest for 5 minutes before slicing it thinly against the grain.
Sauté the Peppers: In the same skillet, add the sliced red and green bell peppers. Sauté for about 3-4 minutes until they are tender but still crisp.
Assemble Quesadillas: Lay one flour tortilla in the skillet over medium heat. On one half of the tortilla, layer with a generous amount of mozzarella cheese, followed by the sliced steak, sautéed peppers, and a drizzle of chimichurri sauce. Sprinkle with cheddar cheese on top, then fold the tortilla over to cover the fillings.
Cook the Quesadillas: Cook for 2-3 minutes on each side until the tortilla is golden brown and the cheese has melted. Repeat with the remaining tortillas and filling ingredients.
Serve: Cut the quesadillas into wedges and serve them hot, garnished with fresh cilantro and additional chimichurri sauce for dipping.
Notes
Feel free to customize the fillings with your favorite vegetables or cheese.