Preheat grill to high heat. Then, in a large mixing bowl, beat the eggs until combined. Add onion, bread, ketchup, Worcestershire, parsley, salt and pepper, and mix well.
Add ground beef, and fold the mixture into the beef until thoroughly combined.
Grab quarter-pound handfuls of the mixture and flatten them into 3/4-inch-thick patties. Lower the grill heat to medium-high, scrape the grates, and lightly oil.
Then place patties on the grill, close the grill lid, and cook 5-6 minutes on each side for medium burgers, adding a minute for more doneness and subtracting a minute for rarer meat. Serve patties on buns and devour them immediately.