Pig's ear topping ex-PM's potato bites (4,6)
I believe the answer is:
hash browns
'potato bites' is the definition.
'pig's ear topping ex-pm's' is the wordplay.
'pig's ear' becomes 'hash'.
'topping' says to put letters next to each other.
'ex-pm's' becomes 'browns' (Gordon Brown).
'hash'+'browns'='HASH BROWNS'
(Other definitions for hash browns that I've seen before include "potato dish" , "breakfast? Part of it, perhaps" .)