Bans bream when cooked with leaves (9)
I believe the answer is:
embargoes
'bans' is the definition.
(I've seen this before)
'bream when cooked with leaves' is the wordplay.
'when cooked' is an anagram indicator.
'with' is a charade indicator (letters next to each other).
'leaves' becomes 'goes' (I've seen this in another clue).
'bream' anagrammed gives 'embar'.
'embar'+'goes'='EMBARGOES'
(Other definitions for embargoes that I've seen before include "Bans" , "Stops" , "Trade barriers" .)