The author of "The Burger Bible" has highlighted the underrated nature of the onion burger, a style that originated in the U.S. around a century ago and has recently taken over Chicago and the surrounding areas. The modern smash burger could take a similar approach to the Oklahoma onion burger which was born in 1922. The onion burger involves placing thinly sliced onions into small beef patties and griddling them until they are coagulated into a grid-like mass of singed beef and soft, charred onions. The use of shredded alliums in these burgers contributes to their savory flavors and contributes to the creation of the smash. The cost savings from the original smash burgers may partly explain their renaissance now. However, there are still precious few onion burgers on Chicago restaurant menus.