Please to be cooked like kippers (6)
I believe the answer is:
asleep
'like kippers' is the definition.
(I've seen this before)
'please to be cooked' is the wordplay.
'to be cooked' indicates an anagram.
'please' is an anagram of 'ASLEEP'.
(Other definitions for asleep that I've seen before include "(Of a limb) numb" , "In slumber" , "Please be at rest (6)." , "Like kippers" , "out like a light?" .)