Cook finally receiving burn (5)
I believe the answer is:
grill
'cook' is the definition.
(grilling is a form of cooking)
'finally receiving burn' is the wordplay.
'finally' suggests the final letters.
'burn' becomes 'rill' (both can mean a stream).
The final letter of 'receiving' is 'g'.
'g'+'rill'='GRILL'
(Other definitions for grill that I've seen before include "Question hard" , "Broil" , "Do well" , "rack" , "Cooking device" .)