Interrogate cook (5)
I believe the answer is:
grill
I believe this clue is a double definition.
'interrogate' is the first definition.
(I've seen this in other clues)
'cook' is the second definition.
(grilling is a form of cooking)
(Other definitions for grill that I've seen before include "Grating" , "Seriously question" , "Cook under a flame" , "Cook by radiant heat" , "rack" .)