I've lately seen some websites in English referring lap cheung (臘腸) simply as the smoked sausage. Sadly, this explanation shows a woeful ignorance of the truth. Lap cheung is so named because it was usually made during the lunar month of December, the 'Lap' Yuen (臘月) in ancient Chinese. It can be 1) wind-dried (most common; cookery classics say the wind can preserve the meat's 'umami' whereas sunlight can enchant its 'scent'), 2) baked or 3) smoked (least common; because the sausage is already well-seasoned). It is a member of the Big Three preserved meat family: the remainder are the Chinese smoked ham (火腿) and the wind-dried duck (臘鴨).
Basically there are two types of Chinese sausage. One is purely made of pork and the other of pork and duck liver mixture, something I reckon as the Chinese take of the 'boudin noir' because it is also almost black in color (though not made of blood). The fat/lean ratio for Chinese sausage used to be half/half, but, thanks to the ever-growing cholesterol censorship nowadays, the ratio is leaning towards the lean side (about 2 fat to 8 lean) -- some even comes up with the 100% fat-free version. Apart from the meat, flavorings such as the soy sauce and notably some mei gwei lu (rose rice wine) are also added to the mixture before filling into the casings.
There are many ways to cook these sausages. Take the duck liver sausage as an example: stir-fry it with greens is of course a brainy one; fry it with glutinous rice and eggs is also a laudable classic... yet the best way to fully appreciate this delicacy is to steam it with plain rice -- it deserves to be treated as chiefly as the black truffle. As banal as it may seem, every sausage connoisseur would agree this is the best way to taste the sausage to its fullest.
And before I forget, here's my definitive short list of the Hong Kong's best Chinese sausage specialists:
to buy all the classics of Chinese sausage and preserved meat you can ever think of, go to:
Wo Hing Preserved Meat Co.
Shop No. 5, 368 Queens Road Central, Sheung Wan
Tel: 2546 8958
to eat the one and only, simply the best and arguably the crispiest duck liver sausage in town, go to:
Se Wong Yee
G/F, 24 Percival Street, Causeway Bay
Tel: 2831 0163