I probably make this sauce more than any other in the book. When I was in culinary school, we were lucky enough to spend a week learning from Yan Kit So, a wonderful cookbook writer and teacher of traditional Chinese recipes and techniques. I have always loved to cook Chinese food—I made my first dim sum feast at age fourteen. From Yan Kit So, I learned to have a better appreciation of simplicity and how good stir-fry technique can add almost as much flavor as sauce.Since I don’t have room to spell out the entire technique in detail, I’ll remind you of the key points here: Prep your ingredients carefully and keep them separate. Use a hot wok and be ready to shake and rock it. Infuse your hot cooking oil with aromatics, but don’t let them burn. The aromatics you use will greatly influence the taste of the finished dish. Don’t assume that everything will take the same amount of time to cook. Don’t overcrowd the pan. Err on the side of thin sauces rather than thick.This recipe is a simple base that can be easily adapted. I use it as written with delicate fresh-tasting vegetables like snow peas, bok choy, or pea shoots. When I want a bolder sauce, I boost it with a dollop of black bean paste or chile sauce. Cornstarch works well as the thickener, but I prefer potato starch because it seems less gluey and the flavor is quite indistinct. Both starches must reach the boiling point, or they will remain opaque and taste raw and starchy.