Tiny writer eating bit of iced fruitcake (6)
I believe the answer is:
minute
'tiny' is the definition.
(minute can mean small)
'writer eating bit of iced fruitcake' is the wordplay.
'writer' becomes 'me' (the person who wrote the clues).
'eating' is an insertion indicator.
'bit of' says to take the initial letters.
'fruitcake' becomes 'nut' (I've seen this before).
The initial letter of 'iced' is 'i'.
'i'+'nut'='inut'
'me' enclosing 'inut' is 'MINUTE'.
(Other definitions for minute that I've seen before include "Small; short time" , "Precise" , "Occupying very little space" , "Little -- 60 18 across" , "It's not very long" .)