McDonald's is selling $1 Egg McMuffins for one day only on Monday, Mar. 2, for the first time, during which customers can buy the classic Egg McMufflein or the savory Sausage McMuffin with Egg breakfast sandwich for $1 through the McDonald’s app. The breakfast item, which is packed with 17-20 grams of protein and contains Canadian bacon, American cheese, and real dairy butter on a toasted English muffin, is an iconic breakfast menu item. The chain also announced its largest burger ever, the Big Arch Burger, which will be rolled out nationwide on Tuesday, March 3.