Lots of sweet powder in brandy's flavouring (5,6)
I believe the answer is:
fines herbes
'flavouring' is the definition.
'lots of sweet powder in brandy's' is the wordplay.
'lots of' means to remove the last letter (the majority of the word).
'sweet powder' becomes 'sherbet' (I've seen this before).
'in' indicates putting letters inside.
'brandy' becomes 'fines' (fine is a type of brandy).
'sherbet' with its final letter taken off is 'sherbe'.
'sherbe' put into 'fines' is 'FINES HERBES'.
(Other definitions for fines herbes that I've seen before include "Addition to stews, etc, for flavour" , "Seasoning mixture" , "tasty combo" , "Maybe chopped parsley" .)