
One of its most distinctive feature is a middle slice of bread ("club" layer) used to stabilize contents and prevent spillage. Customer response to the Big Mac was so good that it rolled-out nationally in 1968.
/https://www.thestar.com/content/dam/thestar/life/food_wine/2017/10/18/is-doomies-vegan-burger-a-healthier-big-mac-alternative-the-dish/big_d.jpg)
It was designed to compete with the similar Big Boy. The Big Mac was created by Jim Delligatti, one of Ray Kroc's earliest franchisees, who was operating several restaurants in the Pittsburgh, Pennsylvania area. The Big Mac Sauce is delivered to McDonald's restaurants in sealed canisters designed by Sealright, from which it is meant to be directly dispensed using a special calibrated "sauce gun" that dispenses a specified amount of the sauce for each pull of the trigger. The name comes from a 1975 advertising campaign featuring a list of the Big Mac's ingredients: "Two all beef patties, special sauce, lettuce, cheese, pickles, onions on a sesame seed bun." The precise recipe for what McDonald's itself now calls Big Mac Sauce remains a secret, but it is recognized as a variant of Thousand Island dressing. Available for a limited time in some countries. Both versions dropped one patty and replaced it with the respective ingredient.

Discontinued in the United Kingdom, limited availability in the United States and Canada (where it is commonly marketed under the name Double Big Mac). Available in Australia, China, Ireland, Serbia, Japan, Turkey, Malaysia, New Zealand and Thailand (Double Big Mac).

