Score surface of steak by making shallow diagonal cuts across the grain about 1 1/2-inches apart to create a diamond-shaped pattern; repeat on second side of steak. In a small bowl, whisk together wine, soy sauce, oil, garlic, parsley and pepper until well combined. Place steak and marinade in a large heavy-duty zip-lock plastic bag. Press out as much air as possible from bag, seal, and massage lightly to distribute marinade and coat steak thoroughly. Place bag in a shallow dish and marinate in refrigerator for at least 8 hours, overnight, or up to 24 hours, turning and massaging occasionally.

Preheat grill with high, direct heat. Grill is sufficiently hot when you can only hold your hand at grill level for only 2 or 3 seconds. While grill is preheating, remove steak from refrigerator and let come to room temperature before grilling (helps ensure meat cooks evenly). When ready to grill, remove steak from marinade, pat dry with paper towels, and season both sides liberally with salt and freshly ground pepper to taste (pressing seasonings into meat with your fingers). Clean grill grate well with wire brush and, to prevent sticking, brush with a light coating of oil.

Place steak on prepared grill grate over a solid bed of hot coals or direct high heat on a gas grill. If using a gas grill, or if your grill has a lid, close it to allow smoke to add it's flavor. Grill steak about 3- to 4-inches* from heat source, for 4 to 5 minutes per side for medium-rare and 6 to 7 minutes for medium (grilling time varies with meat thickness). If desired, to create crosshatch marks, turn steak 45 degrees halfway through grilling on each side. Flank steak is best eaten medium-rare and nicely seared on the outside; flank steak cooked beyond medium will be tough. Do NOT overcook!

To Broil (optional): Position oven rack about 4-inches from heat source, place broiling pan on oven rack, and heat broiler. When ready to broil, remove steak from marinade, pat dry with paper towels, and season both sides liberally with coarse salt and freshly ground pepper to taste (pressing seasonings into meat with your fingers). Place flank steak on hot broiling pan, coated with cooking spray. Leave oven door ajar, and broil 6 to 7 minutes on each side for medium-rare, 9 minutes on each side for medium.

When steak is done to your liking, remove from grill and place on cutting board. Double check doneness by thermometer (rare - 130 to 140 degrees F, medium-rare - 140 to 150 degrees F, medium - 150 to 160 degrees F), or by touch (very rare feels soft and squishy, rare is soft to the touch, medium-rare yields gently to the touch, while medium yields only slightly to the touch and is beginning to firm up). Cover steak loosely with foil and let rest for 5 to 10 minutes (five minutes per inch of thickness), allowing meat juices to redistribute and settle. To serve, slice thinly on the bias (at a sharp angle) and across the grain, and arrange on warmed platter or plates.

* Note: Set distance between heat source and steak according to thickness of meat -- 3-inches or less for a steak 1-inch thick or thinner, 3- to 6-inches for thicker steaks. Thinner steaks require intense heat to form desirable crust before heat has a chance to penetrate and overcook meat, whereas thicker cuts need less heat and longer time to allow middle to cook without burning exterior.

Makes 4 to 6 servings.

Safety Note: Doneness is an issue of personal preference. However, it is recommended that beef be cooked to medium-rare doneness, the internal temperature should reach 145 degrees F to ensure that harmful bacteria have been destroyed. Beef that has been cooked to an internal temperature of 140 degrees F, may be removed from the grill or oven, loosely covered, and allowed to rest a few minutes. The temperature will continue to rise about 5 degrees F, reaching proper doneness.