In a medium bowl, combine onion, steak sauce, Worcestershire sauce, garlic powder, and pepper. Add ground beef; mix well. Shape mixture into four 1/2-inch or 3/4-inch-thick patties.
For a charcoal grill, grill burgers on the rack of an uncovered grill directly over medium coals for 10 to 13 minutes (1/2-inch thickness) or 14 to 18 minutes (3/4-inch thickness) or till meat is done (160 degree F), turning once halfway through grilling. (For a gas grill, preheat a gas grill on high for 10 to 15 minutes. Reduce heat to medium. Place patties on grill rack over heat. Cover and grill as above.)
Serve patties on buns. If you like, top burgers with cheese, tomato, onion, and pickles. Makes 4 servings.