Melt ham and nearly new processed cheese (9)
I believe the answer is:
emmenthal
'cheese' is the definition.
(Emmenthal is an example)
'melt ham and nearly new processed' is the wordplay.
'and' means one lot of letters go next to another.
'nearly' means to remove the last letter.
'processed' is an anagram indicator.
'new' with its last letter taken away is 'ne'.
'melt'+'ham'+'ne'='melthamne'
'melthamne' is an anagram of 'EMMENTHAL'.
(Other definitions for emmenthal that I've seen before include "Swiss cheese with holes" , "Swiss valley giving its name to a cheese" , "Hard Swiss cheese" , "Type of cheese" , "Something cheesy" .)