The easygoing portability achieved by the application of a patty to a bun is central to the burger's appeal. It wasn't until 1921 that Walter Anderson, a cofounder of the White Castle chain, developed the first bun designed expressly for a burger. Nowadays, some 8 billion burger buns are produced each year, and the versions range from sesame seed-dotted domes to crusty artisanal rolls. Kaiser roll The bulk and fluffy interior of this classic bun, good versions of which can be found in most supermarkets, make it an excellent vehicle for big, juicy backyard burgers.