Hams cooked with some potatoes (4)
I believe the answer is:
mash
'some potatoes' is the definition.
(mashed potato)
'hams cooked' is the wordplay.
'cooked' indicates an anagram (letters cooked into a new form).
'hams' is an anagram of 'MASH'.
'with' acts as a link.
(Other definitions for mash that I've seen before include "Crush; soft mixture" , "dish of veg" , "Pureed potatoes" , "TV series" , "Animal feed" .)