Novel written using small pen (5)
I believe the answer is:
scoop
'novel' is the definition.
(Evelyn Waugh novel)
'small pen' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'pen' becomes 'coop' (I've seen this before).
's'+'coop'='SCOOP'
'written using' acts as a link.
(Other definitions for scoop that I've seen before include "Ice cream portion" , "Reporting exclusive" , "Type of ladle" , "Exclusive news item" , "Kind of ladle or shovel-like tool - reporters seek it" .)