icing
noun [ U ] usuk/ˈaɪ.sɪŋ/ (US usually frosting)
糖衣
a sweet food used to cover or fill cakes, made from sugar and water or sugar and butter
chocolate butter icing 巧克力黄油糖衣
Idiom
the icing on the cakeidiom 锦上添花之物
something that makes a good situation even better
I was just content to see my daughter in such a stable relationship but a grandchild, that really was the icing on the cake. 看到女儿与女婿的关系很稳定我已感到满足，后来又添了外孙，这可真是锦上添花。