Crowd-pleasing flank steak gets marinated overnight in soy and garlic before being given a quick turn on the grill.
Whisk soy sauce, oil, lemon juice, garlic, and sliced scallions in a small bowl. Reserve 1/4 cup in a small bowl; cover, and refrigerate. Place steak in a nonreactive 9-by-13-inch dish, pour remaining marinade over meat, and turn steak to coat. Cover, and refrigerate overnight.
Preheat grill to medium-high. (If you are using a charcoal grill, coals are ready when you can hold your hand 5 inches above grill for 4 to 5 seconds.) Remove steak from marinade; discard marinade. Let steak stand, covered, at room temperature for 30 minutes. Season with salt and pepper, and grill to desired doneness, about 7 minutes per side for medium-rare. Transfer to a cutting board, and let stand for 10 minutes.
Coat whole scallions with reserved marinade. Grill, turning frequently, until scallions are tender, about 2 minutes. Discard remaining marinade. Thinly slice steak against the grain, and serve with grilled scallions.