Korean beef bulgogi can be made with any good quality cut of meat. Flank steak is full of beefy flavor, but somewhat tough, but this marinade with some juice from a can of pineapple quickly tenderizes the flank steak.
Heat a grill pan or a skillet over high heat and add the meat slices. Lower the heat as necessary. Cook until the meat is cooked through and slightly caramelized, one to two minutes each side.