Spread, if melting over steak (5,6)
I believe the answer is:
filet mignon
'steak' is the definition.
(filet mignon is a kind of steak)
'spread if melting over' is the wordplay.
'spread' indicates an anagram.
'over' becomes 'on' (physically on top of).
'if'+'melting'='ifmelting'
'ifmelting' is an anagram of 'filetmign'.
'filetmign'+'on'='FILET MIGNON'
(Other definitions for filet mignon that I've seen before include "Small tender boneless cut of beef" , "steak" , "Tender piece of beef" .)