Step 1

In a large heavy skillet, heat oil over medium heat. Add onions and cook, stirring, 5 minutes. Cover, lower heat to medium-low, and cook 15 minutes until onions are soft and beginning to brown. Remove from heat and cool slightly.

Step 2

Place ground beef in a large bowl; add cooked onion and Worcestershire sauce. Mix to combine with your hands. Form into 8 patties; press each patty together firmly. If they are not pressed together firmly, they will fall apart on the grill.

Step 3

Grill, covered, 11 to 15 minutes (over medium heat on preheated gas grill, 13 to 14 minutes) until instant-read thermometer inserted horizontally into center registers 160°F, turning occasionally.