A piece of cake that's presented at kid's party? (6,4)
I believe the answer is:
childs play
'a piece of cake' is the definition.
('child's play' can be a synonym of 'piece of cake')
'presented at kid's party?' is the wordplay.
I cannot really understand how this works, but
'kid's' could be 'childs' ('child' can be a synonym of 'kid') and 'childs' is located in the answer.
'party?' could be 'l' and 'l' is located in the answer.
The remaining letters 'pay' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'that's' acts as a link.
Can you help me to learn more?
(Other definitions for childs play that I've seen before include "A thing that's very easy to do" , "Peter Pan, say, on stage" , "no problem" , "A dramatisation of the nativity" , "Something very easy to do" .)