also: ザーツァイ
noun
zha cai; Sichuan pickled mustard stem
A Chinese pickle made from the stem of a type of mustard plant, often served as a condiment or side dish in Japanese Chinese cuisine.
from Chinese zhàcài
ラーメンにザーサイをのせて食べるのが好きです。
I like to eat ramen with zha cai on top.
中華食材店でザーサイを買ってきた。
I bought some zha cai at the Chinese grocery store.