The secret's in the Chinese pancake: It has to be fresh. The frozen ones get all stiff and crumbly, and the true moo shu headz can spot them a mile away. They've got to be made with the right flour (rice) and should melt in your mouth. Shu Feng knows: They spread the thin, crê pe-esque pancake on a plate, rub (not plop) some hoisin sauce into the pancake, drop a few slices of scallion on top and add a nice dollop of the moo shu mixture -- onions, tofu, sprouts, ginger, garlic and that mysterious sweetness that we can't place -- and wrap it all up to create one of the most heavenly delicacies in the city. Newbies beware of a couple of Shu Feng guidelines: When you are served your helping, don't wait for everyone else to get theirs -- "Eat!" And not with a knife and fork. With your hands. You'll make a mess, but it's a wonderful mess, and the juicy evidence will run through your fingers as you're concentrating on the flavors caressing your tongue.