a desirable feature perceived as the finishing touch to something that is already inviting or worth having
Related Idioms :
a bite at the cherry
an attempt or chance to do something
This phrase is often used in the negative to express the idea that you will not get a second chance (a second bite at the cherry). If you take two attempts to do something, especially some quite small task, this is taking two bites at the (same) cherry or another bite at the cherry.
a bowl of cherries
a very pleasant or enjoyable situation or experience