The onion burger's creation is debated. Invented during the Great Depression as a way to offset the cost of beef or the marketing gimmick of an El Reno establishment to get travelers on Route 66 tasty meals, the onion fried burger has become a beloved staple of Oklahoma. Route 66 is the most iconic road in America, and El Reno is known as the Crossroads of America! This small town has a big personality, and the restaurants serving this iconic dish have served as the heartbeat of the community through all of the ups and downs.