Poet who cooked steak (5)
I believe the answer is:
keats
'poet' is the definition.
(John Keats)
'cooked steak' is the wordplay.
'cooked' indicates an anagram (letters cooked into a new form).
'steak' anagrammed gives 'KEATS'.
'who' acts as a link.
(Other definitions for keats that I've seen before include "Endymion, Lamia poet" , "One of two born together" , "Author of Endymion and Ode to a Nightingale" , "Grecian Urn poet" , "To a Nightingale poet" .)