Sid’s Diner
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The Oklahoma onion burger, a regional favorite, is a hamburger patty with paper-thin slices of Spanish white onion smashed into the meat. According to legend, the onion burger was invented by Ross Davis in the 1920s at the Hamburger Inn in Ardmore, Oklahoma. During the Depression, onions were cheap and hamburger meat was expensive. Ross came up with the thrifty idea of adding onions to the burgers and smashing them into the meat with the back of his spatula. Called Depression burgers, Ross would pound a half onion's worth of shreds into a 5-cent burger. The ground meat and onions cooked together, infusing the patty with the onion until the burger seared around the edges and the onions caramelized and crisped. Some of the most famous and popular onion burgers today come from Sid’s Diner in El Reno, Oklahoma. Known for its burgers and shakes whipped up in a homey, old-timey space with counter seats, cooks place a slice of American cheese and a bun on a 6-oz. patty and let the cheese melt while the onions and meat brown and the bun soaks up the juices. A history junkie’s dream, the diner’s décor boasts more than 450 photographs of the Oklahoma land lotteries, cowboys on horseback, and the early days of car culture when El Reno was a major stop along Route 66.