Cook some cobra keenly, not rare (4)
I believe the answer is:
bake
'cook' is the definition.
(baking is a kind of cooking)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for bake that I've seen before include "Cook cake or bread" , "Cook (eg, bread)" , "Cook (cakes, etc)" , "Cook by dry heat in an oven" , "Cook (eg, cakes)" .)