<Li> In Minnesota, a "Juicy Lucy" (or "Jucy Lucy", depending on which restaurant's origin claims is to be believed) is a hamburger with cheese inside the meat patty, rather than on top . A piece of cheese is surrounded by raw meat and cooked until it melts, resulting in a molten core of cheese within the patty . This scalding hot cheese tends to gush out at the first bite, so servers frequently warn patrons to let the sandwich cool for a few minutes before consumption . </Li> <Li> Buffalo burgers are made with meat from the American bison . </Li> <Li> A low carb burger is a hamburger with the bun omitted, and large pieces of lettuce used in its place, with mayonnaise and / or mustard being the primary sauces used . </Li>

When was the hamburger introduced in the united states