Cook; interrogate (5)
I believe the answer is:
grill
I believe this is a double definition.
'cook' is the first definition.
(grilling is a form of cooking)
'interrogate' is the second definition.
(I've seen this before)
(Other definitions for grill that I've seen before include "quiz?" , "Means of cooking" , "Cook under direct heat" , "Question closely" , "Screen" .)