Avails oneself of some porterhouse steak (4)
I believe the answer is:
uses
'avails oneself of' is the definition.
(I've seen this in another clue)
'some porterhouse steak' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'USES' is hidden within 'porterhouse steak'.
(Other definitions for uses that I've seen before include "Functions, applications" , "Puts to a particular purpose" , "Employs" , "Puts into service" , "Sues (anag.)" .)