Some continental custard powder (4)
I believe the answer is:
talc
'powder' is the definition.
(talcing is a kind of powdering)
'some continental custard' is the wordplay.
'some' indicates the answer is hidden within the clue (some parts of the word are used).
'TALC' is hidden in the letters of 'continental custard'.
(Other definitions for talc that I've seen before include "(Mineral providing) powder" , "Powdered mineral" , "Bathroom powder (abbr)" , "Cosmetic powder" , "Soft mineral; powder" .)