In a large glass baking dish combine onion, beer, chili sauce, parsley, mustard, Worcestershire sauce, brown sugar, paprika, and the 1/2 teaspoon pepper. Place steaks in marinade. Cover and refrigerate 4 to 6 hours or overnight, turning steaks over occasionally.
Remove steaks from marinade; discard marinade. Sprinkle both sides of steaks with the cracked black pepper.
Grill steaks on an uncovered grill directly over medium-hot coals for 5 minutes. Turn and grill to desired doneness, allowing 7 to 10 minutes more for medium (160 degrees F) doneness. If desired, garnish with fresh herbs. Serves 6.