1 1/2 pounds ground beef
1 tablespoon Worcestershire sauce
3/4 teaspoon garlic salt
1 teaspoon black pepper
Combine ground beef, Worcestershire sauce, garlic salt, and pepper in a large bowl; mix well. Form 8, thin patties from the beef. Each patty should be slightly larger than a slice of cheese.
Cut each slice of cheese into 4 equal pieces; stack the pieces. Sandwich one stack of cheese between 2 ground beef patties. Tightly pinch edges together tightly seal the cheese within the meat. Repeat with the remaining cheese and patties.
Preheat a cast-iron or other heavy bottomed skillet over medium heat. Cook burgers until well browned, about 4 minutes. It is common for burgers to puff up due to steam from the melting cheese. Turn burgers and prick the top of each to allow steam to escape; cook until browned on the outside and no longer pink on the inside; about 4 minutes.
For the juiciest burgers, be sure your ground beef is at least 20% fat.
Did you make a tight seal? I hope so, because it needs to be TIGHT to avoid a cheesy eruption as the cheese melts, creates steam, and tries to find its way out.
You can also fire up a medium-hot bed of coals and cook these on your backyard grill.