Hams cooked with potatoes (4)
I believe the answer is:
mash
'potatoes' is the definition.
(I've seen this before)
'hams cooked' is the wordplay.
'cooked' indicates an anagram.
'hams' with letters rearranged gives 'MASH'.
'with' is the link.
(Other definitions for mash that I've seen before include "Soft, pulpy mass" , "Crush, potatoes say" , "Food for horses" , "Pureed potato" , "TV series" .)