Puree (4)
(Other definitions for mash that I've seen before include "Bangers' frequent partner?" , "Pulped potatoes" , "Accompaniment of bangers" , "Pummel" , "Sham sort of pulp" .)
'puree' is the definition.
(thesaurus)
This is all the clue.
(Other definitions for pulp that I've seen before include "Nonsense" , "Soft moist mass, may be crushed" , "Mush" , "Crush" , "Soft fleshy part of a fruit" .)