noun
tenkasu; tempura scraps; crunchy fried batter bits
Small bits of batter left over from frying tempura; used as a topping or ingredient in dishes like takoyaki, okonomiyaki, and udon.
See also: 天ぷら
うどんに天かすをのせて食べるのが好きです。
I like eating udon with tenkasu on top.
お好み焼きに天かすを入れると、サクサクした食感が加わります。
Adding tenkasu to okonomiyaki gives it a crunchy texture.
Tempura is the dish itself; tenkasu are the leftover fried batter bits produced when making tempura.
Compound of 天 (ten, abbreviation of 天ぷら tempura) and かす (kasu, 'dregs' or 'scraps').