There are a number of very specialized restaurants popping up in Koreatown, and one of the best is Master Ha, or Ha Sun Saeng, which focuses most of its energy on a soup called seolleongtang. The dish starts with a base of bone broth — or, you know, stock. Beef (typically oxen) bones are simmered for about a day to create the soup, to which slices of beef are added. The broth traditionally is an off-white, opaque color, but at Master Ha seolleongtang also comes in a brick-red spicy variety. Either way you order it, the soup comes to the table boiling hot. There isn't much in it beyond the generous portion of meat: a few vegetables and a handful of noodles. You can, of course, gussy it up with the selection of banchan: both cabbage and root vegetable kimchi, various pickles and dried herbs. (The spicy version comes with an egg.) But taste the soup first — you may find that you appreciate the extremely clean beef flavor unadorned.