Today's dish is a simple but delicious cold dish — beancurd with century egg (preserved duck egg). As I've explained previously, 皮 (pí/skin/leather/rind) in combination with 蛋 (dàn/egg) refers to duck eggs cured in a high-pH coating, leaving the whites "cooked" through to a translucent amber and the yolks dark green and creamy. I also discussed 豆腐 (dòu fu/beancurd) a while back.
皮蛋豆腐 is not complicated to make, but relies heavily on the quality of the ingredients. You want to use a fairly soft beancurd for this, and you want it to be as fresh as possible. Don't use the type that's marketed as a meat substitute (Cauldron brand, etc), as the texture is wrong, and also be careful about using aseptically-packaged brands, as many of them have a characteristic and (in my opinion) unpleasant flavour. Similarly, make sure that you like the taste of your century eggs on their own before using them in this dish.
Slice or cube the beancurd, then arrange it in a serving dish. Shell the century eggs, then halve, quarter, or chop them and arrange them on top of the beancurd.
The sauce for the dish is simply a mixture of soy sauce with sesame oil and/or Chinese black vinegar and/or a little chilli oil. You can garnish it with spring onions, either just the green parts or white and green together. I've also seen some recipes on the internet that add pork floss as a garnish, but I've never seen this in a restaurant (update, May 2011: I have now — at Leong's Legend, a Taiwanese restaurant in London Chinatown).