Tempura is simple: coat food in batter and deep-fry it. Yet from that very simplicity arises the subtlety and difficulty of the craft. Green asparagus spears are plump with flavoursome moisture; drop the spears into hot oil and their moisture quickly heats up, turns to steam and leaps from the fryer. The role of the coating, and the essence of tempura, is to capture that delicious moisture and concentrate it. Experience cultivated through training turns tempura from good to magnificent.