Combine oil, soy sauce, water, brown sugar, ginger, garlic, and pepper in a small bowl. Mix until combined.

Cut shallow slashes in a crosshatch pattern on both sides of the steak, being careful not to cut all the way through.

Place steak in a low, flat dish and pour marinade on top, covering meat completely. Cover and refrigerate at least 4 hours, or overnight, turning steak over once.

Set an oven rack about 6 inches from the heat source and preheat the oven's broiler. Remove steak from the marinade and place on a baking pan. Reserve marinade.

Broil, brushing occasionally with marinade, until browned and heated through, about 5 minutes per side. Remove steak to a platter and cover loosely with foil. Let rest for at least 5 minutes. Slice into 1- to 2-inch strips across the grain.