1
Preheat grill to 400F degrees.
2
Divide beef into six portions. Roll one portion of meat between hands, working it together to create a tightly formed ball (the beef should not be crumbly). Divide ball in half, forming one half into another ball and then flattening it into a large circle on a cutting board (should be larger than the bun size, as the beef will shrink a bit during cooking).
3
Fold one slice of American cheese into quarters and arrange the cheese in the center of the beef, overlapping the slices a bit to leave the beef edges exposed. Roll the other half of the beef into a ball and flatten into a circle the same size as the first, then lay it onto top of the cheese. Pinch the edges of beef together, sealing all holes. You will have a lump in the top of the patty where the cheese lies inside. Repeat with the rest of the beef to create six lucy patties into total. (Burger patties can be made in advance and then refrigerated until ready for grilling.)
4
Place burger patties on grill, pocket of cheese side up. Sprinkle each patty with steak seasoning. Close lid and grill for 8-9 minutes, then flip burgers. Pierce each patty once with a sharp knife to let out the steam from the melting cheese. Close lid and continue cooking 7-8 minutes longer. At this point, you can either move the patties to a low heat on the grill to keep until ready to serve or pull them off onto a clean plate and cover with foil.
5
To assemble: If serving with optional toppings, lay pickle slices on bottom half of bun, followed by fried onions and then one jucy lucy patty and the top of the bun.
