Cook finished batter (2,4)
I believe the answer is:
do over
'batter' is the definition.
(both can mean to assault or attack)
'cook finished' is the wordplay.
'cook' becomes 'do' (I've seen this in other clues).
'finished' becomes 'over' ('over' can be similar in meaning to 'finished').
'do'+'over'='DO OVER'
(Other definitions for do over that I've seen before include "mug" , "Decorate" .)