I ran across this recipe written by Michael H. who is the nephew of the owner of Hussey's Harbour House.
1.5 pounds of 80% ground chuck - not leaner!
2 teaspoons Kosher salt
Lettuce and tomato
Cheese - American is fine
Potato bun, lightly toasted
Dijon mustard mixed with a little mayo and horseradish
Lightly mold the burger into 4 patties about 4 to 5 inches across and press down with your thumb in the middle of each patty so that they do not turn into baseballs as they cook. Sprinkle the Kosher salt, an essential ingredient. Preheat a gas grill or start the charcoal . The fire should be quite hot; you should barely be able to hold your hand 3 inches over the rack. Put the burgers on the rack and grill about 5 minutes per side. Flip over only once. Never, ever press down on the burgers as they cook! Place cheese on the burger for the last minute. Dress with the sauce. Get plenty of napkins as this juicy burger will flow!