- Portion size 4 servings
In bowl, beat egg with fork; mix in bread crumbs, salt, pepper, onion, vinegar and Worcestershire sauce. Mix in ground beef.
Shape into four 1/2-inch (1 cm) thick patties. Place on greased grill over medium-high heat; close lid and cook, turning once, for about 10 minutes or until no longer pink inside.
Add cheese and Spanish onion. Place each in bun.