Trace of some white chocolate (4)
I believe the answer is:
echo
'trace' is the definition.
(echo can mean a trace or hint of something)
'some white chocolate' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'ECHO' is hidden in the letters of 'white chocolate'.
'of' is the link.
(Other definitions for echo that I've seen before include "Radio operator's word for 'E'" , "Let's hear it again for the Greek nymph who loved Narcissus in vain" , "Ape" , "Reminder" , "Sound returning some moments later" .)