Snigger about raised surface of biscuit (6,4)
I believe the answer is:
ginger snap
'biscuit' is the definition.
(I know that ginger snap is a type of biscuit)
'snigger about raised surface' is the wordplay.
'about' is an anagram indicator.
'raised surface' becomes 'nap' (raised threads on cloth).
'snigger' with letters rearranged gives 'gingers'.
'gingers'+'nap'='GINGER SNAP'
'of' acts as a link.
(Other definitions for ginger snap that I've seen before include "Spicy biscuit" , "quick bite" .)