What is "janggukjuk"

Janggukjuk or Jangguk jook is a variety of juk , or Korean porridge, made with pounded non-glutinous rice (as opposed to glutinous rice), beef and brown oak mushrooms. Janggukjuk is seasoned with soy sauce, and it literally means soy sauce porridge. It is high in protein and therefore believed to be good for recovering patients and the elderly.