Rascal beginning to ingest breaded prawns (6)
I believe the answer is:
scampi
'breaded prawns' is the definition.
(I've seen this before)
'rascal beginning to ingest' is the wordplay.
'rascal' becomes 'scamp' ('scamp' can be a synonym of 'rascal').
'beginning to' says to take the initial letters.
The first letter of 'ingest' is 'i'.
'scamp'+'i'='SCAMPI'
(Other definitions for scampi that I've seen before include "Dish of crustaceans" , "Dish of deep-friend prawns" , "Prawns (fried with breadcrumbs)" , "Dish of cooked shrimps or prawns" , "Norway lobsters -- Dublin Bay prawns" .)