"It's two griddled burger patties," he said. "Very often, a sixth of a pound each, very common, commercial, small, usually frozen patties, griddled on a flat top. It comes on a toasted sesame seed bun. Almost every place will lightly toast the bun on the griddle as the burger is cooking. When the burger is almost finished cooking, the bottom of the bun will be taken off and dressed with ketchup, mustard and, usually, two or three pickle coins. Then the two burgers will be taken off with a piece of American cheese sandwiched between, and then that burger-cheese-sandwich will be placed on the bottom bun. Then everything is topped with a tong-full of sauteed onions, pretty greasy, not browned but colored, and then the top of the bun goes on. The order of the assembly at the authentic places is really invariant."