[Image: Thick, flat, translucent noodles piled on a plate and topped with slivers of stirfried pork, dried red chillies, and fresh coriander. A fluid brown sauce coats the noodles and pools on the plate.][see footnote]
As well as letting myself off having a theme for this week, I'm also letting myself off the requirement to know exactly how today's dish is made. Which is handy, since I've only ever had it in one restaurant, and I can't find any recipes for it. (Edit, June 2011: Out To Lunch has a recipe for 雞絲拉皮/jī sī lā pí, which is similar but uses chicken.)
東北拉皮 (Dōngběi lā pí) is a cold dish of thick, flat, translucent mung bean noodles dressed with various tasty things and served mixed with shredded cucumber and stirfried pork slivers. I think it's delicious, though the heavy, slippery noodles can be somewhat tricky to eat without making a mess!
東北 (Dōngběi) means "northeast" (though it's the other way around from the English — 東 is "east" and 北 is "north"). In this context, it refers to a group of three provinces tucked up alongside Inner Mongolia in the far northeast of China: Liáoníng, Jílín, and Hēilóngjiāng.
拉皮 refers to the type of noodles; literally "pulled [拉] skin [皮]". They seem to sometimes also be called 大拉皮 (dà lā pí); 大 means "big". Another name for these noodles is 粉皮 (fěn pí), which translates as something like "starch [粉] skin [皮]". Like 粉絲 (fěn sī/bean thread noodles), 粉皮 are made from mung bean starch; however, 粉皮 are much thicker and more robust than 粉絲. (Londoners: I found 粉皮 in Loon Fung in Chinatown.)
There seem to be a few versions of this dish; for example I found one photo on Flickr that includes shredded ham, omelette, carrots, and cucumber, as well as prawns. Beijing Haochi has a post on Xian Lao Man restaurant that features a version closer to the one I'm familiar with; the sauce ingredients listed there are black vinegar and sesame paste (the internet tells me that Chinese sesame paste is similar to tahini but made with toasted rather than raw sesame seeds). Eating Asia also lists vinegar and sesame paste as ingredients, with the addition of "la jiao" (辣椒/chillies) and raw garlic. As Bejing Haochi mentions, the key to success in making 東北拉皮 is the texture of the noodles; they shouldn't be too hard, but neither should they be mushy.
I've also found reference to a dish called 西北拉皮 (xī běi lā pí) — 西北 means "northwest". This appears to be a different dish; it's the same noodles, but topped with a sweet and spicy sauce, served hot. I'm not sure what's in the sauce.