Heat BBQ grill or stove-top grill to medium-high.
Combine ground beef, Worcestershire sauce, salt, and pepper.
Make two equal-sized patties.
Drop small pieces of the butter equally on each burger and push it in slightly with your thumb.
Place patties on the grill butter side up.
Grill both sides to your desired temperature.
When burgers are almost done, place 1 slice of cheese on each burger and continue to cook until the cheese begins to melt.
While burgers are cooking, brown the hamburger buns by splitting them in half and placing them face down on the grill for a few minutes.