Theta burger is the name of an Oklahoma specialty consisting of a bread bun and a meat patty that is topped with hickory sauce, mayonnaise, slices of dill pickles, and shredded cheddar cheese. It is believed that the burger originated in the Split-T restaurant (now closed) in Oklahoma City, although some claim that it was invented in the 1930s or the 1940s by Ralph Geist, the owner of Town Tavern in Norman, Oklahoma.