Sirloin, e.g. (5)
(Other definitions for beef that I've seen before include "Small errand" , "Complain; meat" , "Meat of the cow" , "Muscle; meat; grievance" , "Grumble - muscle" .)
(Other definitions for steak that I've seen before include "Good beef" , "Portion of meat" , "Slice of meat or fish" , "Fleshy piece of meat" , "Takes (anag.)" .)