Sweet spice, perfect (10)
I believe the answer is:
peppermint
'sweet' is the definition.
(peppermint is a kind of sweet)
'spice perfect' is the wordplay.
'spice' becomes 'pepper' (peppering is a kind of spicing).
'perfect' becomes 'mint' (as in mint condition).
'pepper'+'mint'='PEPPERMINT'
(Other definitions for peppermint that I've seen before include "herb" , "Aromatic plant" , "flavour" , "Pungent sweet" , "Sweet flavoured with aromatic oil" .)