For this recipe, I prefer medium Chinese eggplants, the pale purple, slender ones that are ten to twelve inches long, over similar-looking but more bitter varieties. This calls for oil-blanching and, because eggplant is basically a sponge, brining them for an hour first until they are saturated but not bloated. During frying, the water turns to steam and makes the eggplant creamy and not at all oily. Cooking is really the study of water. It takes water to grow everything, of course, and so the amount of water that remains in an ingredient after it is harvested or butchered dictates how it will heat through in the pan, whether it will soften, seize, crisp, or caramelize. You're adding water when you use stocks, vinegars, or alcohol. You're creating barriers to water with starches. How you cut ingredients and the order in which you add them to the pan is about controlling how and when they release the water inside them. Even the shapes of cooking vessels are about releasing or retaining moisture. When cooking with a wok, changes to water happen so quickly that split-second timing is essential.