Cut the bacon up, eating one (9)
I believe the answer is:
aitchbone
'cut' is the definition.
(aitchbone is a kind of cut)
'the bacon up eating one' is the wordplay.
'up' is an anagram indicator (letters get chucked up).
'eating' means one lot of letters goes inside another.
'one' becomes 'i' (Roman numeral).
'the'+'bacon'='thebacon'
'thebacon' anagrammed gives 'atchbone'.
'atchbone' enclosing 'i' is 'AITCHBONE'.
(Other definitions for aitchbone that I've seen before include "Cut of meat" , "cut of beef" .)