A quantity of brutal chilli powder (4)
I believe the answer is:
talc
'a quantity' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
'of brutal chilli powder' is the wordplay.
'of' says the answer is hidden in the clue.
'TALC' is hidden in the letters of 'brutal chilli powder'.
Can you help me to learn more?
(Other definitions for talc that I've seen before include "Drier" , "White powder for the bathroom" , "Mica - scented body powder" , "Powder used as toiletry" , "I may dust" .)