The street food of Southeast Asia is great for those of us who like to graze on small snacks in addition to our main meals. I justify such frequent eating by telling myself of the need to keep my blood sugar level at a constant so that I won't be grouchy towards my travelling companions. But with some street snacks, there's no need to feel guilty. In Malaysia and Singapore, the popiah is a good, somewhat healthy snack, and it's interesting to see how each vendor customises his or her speciality. Although I love fried foods, I prefer the more basic version of popiah, which has a thin, white wrapper stuffed with a mix of vegetables, resulting in a variety of textures and flavours. Crisply fried shallot is de rigueur in popiah and sliced fried beancurd is used in most versions, as is shredded thin egg omelette (although you can tell the vendor to omit these or any other ingredients). Some vendors add small bits of meat or seafood. All the flavours are bound together by a thick, sweet-salty-spicy, rich, dark sauce drizzled over the vegetables just before the popiah is rolled. The sauce should be used judiciously - too little and the popiah will be dry; too much and the subtle flavours of the vegetables will be overwhelmed. If you're trying to decide between competing vendors (they frequently set up 'shop' near each other), it's wise to go with the crowd - if one has a long line and the other doesn't, there's probably a good reason.