What is "undercooks"

Usage examples of "undercooks".

He'd arrived in the Blues' kitchens and cellars, spent a day glaring at what he found, thrown out almost all of the implements, much of the wine, dismissed all but two of the undercooks, terrified the boys, and-within days-had begun producing meals that dazzled and amazed.

Kyros saw that the two undercooks and the other boys had each grabbed some sort of weapon.