Stir the mayonnaise, ketchup, relish, and Worcestershire sauce together in a bowl to make the spread. Set aside.
Mix the ground chuck, salt and pepper together with your hands in a bowl. Form the meat into 4 thin quarter-pound patties, each about 4 inches in diameter and 1/2 inch thick.
Heat a large cast iron skillet or griddle over medium-high heat for at least 5 minutes until very hot. Add as many patties as will fit comfortably — do not crowd — and cook for about 2-3 minutes, until the sides of the burger patty are opaque.
Flip each burger patty and top with a slice of American cheese, if desired. Cook until the cheese begins to droop and melt at the corners and edges. Repeat with the remaining burgers and cheese.
While the burgers cook, slather the bottom half of each bun with about 1 tablespoon spread. To build each burger, top the spread with 2 tomato slices, 1 lettuce leaf, the cooked burger, 1 slice of onion, and finish with the top bun. Serve immediately.
WANT TO MAKE YOUR BURGER ANIMAL-STYLE?
Brush both sides of your burger patty lightly with yellow mustard before it hits the griddle. Increase the amount of spread on the bun to 1 1/2 tablespoons each, and throw a few round dill pickle slices on top of the spread before topping with tomato. Substitute the raw white onion slices for caramelized onions (about 2 tablespoons per burger), and you've got an animal-style burger.