All that's left of prime steak? (4)
I believe the answer is:
rump
I believe this is a double definition.
'all that's left' is the first definition.
(rump can mean a remainder or remnant)
'prime steak?' is the second definition.
(rump is a type of steak)
'of' is the link.
(Other definitions for rump that I've seen before include "Hind part; small remnant" , "Inferior remains; cut of steak" , "Posterior" , "Cut of meat form animal's hindquarters" , "Cut of meat from the rear" .)