Notices Christmas fare if served with mint, did you say? (5)
I believe the answer is:
spies
'notices' is the definition.
(I've seen this in another clue)
I can't explain the rest of the clue.
(Other definitions for spies that I've seen before include "Secret agents" , "Snoops" , "Eg, CIA" , "Undercover agents" , "Double agents" .)