Hamburger Cheese (usually processed cheese slices but often Cheddar, Swiss, pepper jack, or blue), either melted directly on the meat patty or crumbled on top, is generally an option. Condiments might be added to a hamburger or may be offered separately on the side including mustard, mayonnaise, ketchup, salad dressings and barbecue sauce. Other toppings can include bacon, avocado or guacamole, sliced sautéed mushrooms, cheese sauce, chili (usually without beans), fried egg, scrambled egg, feta cheese, blue cheese, salsa, pineapple, jalapeños and other kinds of chili peppers, anchovies, slices of ham or bologna, pastrami or teriyaki-seasoned beef, tartar sauce, french fries,
Hamburger some Australian themed pubs even kangaroo burgers can be purchased. These burgers are served in a similar way to the traditional hamburger but are sometimes served with a different sauce including redcurrant sauce, mint sauce and plum sauce. In the early 21st century "premium" hamburger chain and independent restaurants have arisen, selling burgers produced from meat stated to be of high quality and often organic, usually served to eat on the premises rather than to take away. Chains include Gourmet Burger Kitchen, Ultimate Burger, Hamburger Union and Byron Hamburgers in London. Independent restaurants such as Meatmarket and Dirty Burger developed