Thin noodle (mian4 xian4) recipe?

Does anyone have a thin noodle recipe (preferably vegetarian)? While my wife and I are in the US, my wife would like to cook this favorite dish of hers. In Taiwan, you can find street vendors scooping this soupy noodle dish from out of big caldrons on a cart. The soup is thick with wheat noodles, toufu, mushrooms, etc.