Heat a large, heavy skillet over medium-high heat until it begins to smoke. Add steak, and cook until nicely browned, 1 to 2 minutes. Turn and cook until browned on the other side, 1 to 2 minutes. Remove from heat and transfer steak to a plate and set aside.
When the skillet has cooled slightly, return it to the stove over medium-low heat. Add the butter; when it melts, add the ginger and saute for about 30 seconds. Add the soy sauce, and stir with a spoon until thick. Return the steaks to the skillet along with any accumulated juices. Increase the heat to medium and cook, turning the steak after 3 or 4 minutes for medium rare. Transfer the steak to a serving dish with the pan juices spooned over the steak. Garnish with fresh cilantro leaves.