Concave cooker (3)
I believe the answer is:
wok
'concave cooker' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for wok that I've seen before include "Pan used in Chinese cookery" , "pot" , "Asian cooking pan" , "Stir-fry pan" , "A Chinese large-bowled frying pan" .)