Burger King's Quad Stacker, a sandwich that combines four beefy patties with four American cheese slices and is topped with bacon and Stacker Sauce, has been discontinued from the chain's menu since 2006. However, since BK still stocks all components, you can order off-menu. While some fast food enthusiasts are less than excited about the secret menu trend, many chains continue to offer "secret" items. BK is open to creative customization, allowing standard condiments or special sauces to be swapped to create a new flavor profile for any sandwich. Some modifications can take a little more work but may be worth it to enhance the experience.