Aromatic herb with flat or crinkly leaves (7)
I believe the answer is:
parsley
'aromatic herb with flat or crinkly leaves' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for parsley that I've seen before include "Aromatic herb with flat or crinkly leaves" , "Herb (flat-leafed or curly)" , "You might misuse this herb sparely" , "Herb with either flat or crinkly leaves" , "Cow -, fool's - and stone - are all plants" .)