Perhaps some Brownie in child’s play (1,5,2,4)
I believe the answer is:
a piece of cake
'perhaps some brownie in child's play' is the definition.
I can't tell whether this defines the answer.
'some brownie in child's play' is the wordplay.
I cannot really see how this works, but
'some' could be 'a' and 'a' is found in the answer.
'child's play' could be 'pieceofcake' (synonyms) and 'pieceofcake' is found within the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for a piece of cake that I've seen before include "A walk in the park" , "part of Dundee?" , "... easy thing to do" , "Not much to eat" , "Something that is easily obtained" .)