Pad Thai is essentially a stir-fry and requires little more than chopping and stirring. It comes together in less than a half-hour. Some ingredients in this recipe may be unfamiliar. The first are the noodles themselves: rice stick noodles, which are pale, translucent, flat and range from very thin to more than a quarter-inch wide. Unlike semolina pasta, rice stick noodles don’t need to be boiled; instead, you soak them in hot water until they’re tender. Meanwhile, make a sauce from tamarind paste, now easily found in larger supermarkets or online. The paste, made from the pulp of the tamarind pod, is very sour, but more complex than citrus. It can vary widely in its potency, so be sure to taste as you go. Fish sauce (nam pla) is another important ingredient. Made from fermented anchovies (and much like the garum of ancient Rome), it has an unappealing smell and a fabulous taste. Honey and rice vinegar round things out.