These quesadillas are a perfect way to enjoy leftover carne asada. Mincing the meat into bite-sized pieces ensures every bite is full of flavor. Plus the grilled chayote and traditional Mexican cheese make these quesadillas rich and warm.
In a bowl, combine salsa casera, butter, lemon and lime juice, serrano, garlic, cilantro, and onion and mix well.
Place beef in a large bowl and pour the marinade over beef. Massage marinade around so that the beef is well-covered and cover bowl. Let stand at room temperature for 30 minutes or in the refrigerator for up to 2 hours.
Preheat a grill or grill pan to high. Season steak with salt and pepper. Grill the steak for 3 to 5 minutes per side for medium-rare, depending on thickness of meat. Let rest 5 minutes, and then slice the meat against the grain into 1/2-inch pieces.
Brush the chayote slices with olive oil. Season them with salt to taste. Place the chayote slices on the grill or griddle pan and cook them for 10 to 15 minutes, turning once halfway through the cooking time.
Place a dry griddle or cast-iron skillet over medium-high heat. Place a tortilla on the skillet and top with cheese. Add 2 to 4 strips of carne asada and grilled chayote. Place another tortilla on top. Cook until light golden, about 2 to 3 minutes or until cheese melts. Flip over and cook until golden brown.
Serve warm and, with salsa, guacamole, and sour cream.
Nutrition facts do not include any optional toppings.
Look for chayote squashes at Latin American and Asian markets.