caster sugar就是我们日常生活中常见的细白砂糖。

【例句】
Cover a baking sheet or tray with a sheet of nonstick baking parchment sprinkled liberally withcaster sugar.
在烘培板或者烘焙盘上盖一片不粘的烘焙纸，均匀地撒上细白砂糖。

Whisk the egg white, add in caster sugar gradually, continue whisk until stiff peaks form.
将蛋白打发至发泡，细砂糖慢慢加入，继续打发至硬状。