Hey Sheldon. Although both burgers use two beef patties, they each have their own unique toppings and dressings. The buns are also different - the Big Mac uses a sesame seed bun and the McDouble uses a regular bun. The Big Mac also comes with shredded lettuce, our signature Big Mac Sauce, pickles, one slice of cheese and onions. The McDouble has ketchup, mustard, one slice of cheese, pickles and onions. The McDouble is also part of our Value Picks menu!