Lay the bacon in a medium cast-iron skillet and cook over medium heat, turning once, until golden and crispy, about 5 minutes per side. Transfer the bacon to a paper-towel-lined plate and pour off some of the bacon drippings, leaving enough in the pan to just cover the bottom.
From the top and 3 sides of the head of lettuce, cut 4 thick round slices, each 4 to 5 inches across, to use as buns and set aside. (Chop up and reserve the remaining "square" of lettuce for salads or another use.)
Shape the ground beef into 2 patties, each about 4 inches across and 3/4 inch thick, and sprinkle both sides with salt and pepper.
Heat the skillet over high heat and once hot, add the patties and cook for 3 minutes per side for medium-rare.
Lay a lettuce "bun" cut-side up on each of 2 plates and top each with a burger patty. Spoon 1 tablespoon of the dressing over each burger and top each with half of the onion, 1 slice of the tomato and 2 pieces of the bacon. Top with the remaining lettuce buns.
Copyright 2016 Television Food Network, G.P. All rights reserved.