Deep-frying (zhà), a well-known technique where the food is fried in a pool of hot oil, which both cooks it and creates a crispy exterior, is used throughout the ‘Frying’ chapter in my cookbook The Chinese Way. When deep-frying, I use a thermometer and aim for 350°F to 375°F. Another way to gauge the temperature is to stick a wooden chopstick in the oil and, if tiny bubbles float rapidly up around it, the heat is adequate.