How to Make It
In a bowl, mix ground beef, egg, onion, bread crumbs, Worcestershire, garlic, 1/2 teaspoon salt, and 1/4 teaspoon pepper until well blended. Divide mixture into four equal portions and shape each into a patty about 4 inches wide.
Lay burgers on an oiled barbecue grill over a solid bed of hot coals or high heat on a gas grill (you can hold your hand at grill level only 2 to 3 seconds); close lid on gas grill. Cook burgers, turning once, until browned on both sides and no longer pink inside (cut to test), 7 to 8 minutes total. Remove from grill.
Lay buns, cut side down, on grill and cook until lightly toasted, 30 seconds to 1 minute.
Spread mayonnaise and ketchup on bun bottoms. Add lettuce, tomato, burger, onion, and salt and pepper to taste. Set bun tops in place.
If you want absolute bacteria safety, you need to cook your burgers to 160°. This recipe will keep them moist.