Two all-beef patties, special sauce, lettuce, cheese, pickles, onions, on a sesame seed bun. That’s the Big Mac that you know and love. McDonald’s just announced they’re going to be serving two alternative versions of the Big Mac for a limited time. The Little Mac is just one patty and no extra bun. There is also the Double Big Mac, which is four patties, two above the extra bun, two below. They are on sale now.