For a short time only, when you place an order at Whataburger that contains 2 a la carte Breakfast On A Bun sandwiches, you'll be able to get 1 of those sandwiches for free.
This offer can be accessed in-restaurant by showing the scannable "Barcode" section in your Whataburger App. You can also redeem it online through the Whataburger app or your online Whataburger account.
Whataburger's Breakfast On A Bun comes with one egg, a sausage patty and a slice of real American cheese. It is served on a fresh, 4 inch bun.