Cora Abel cooked a tuna (8)
I believe the answer is:
albacore
'a tuna' is the definition.
(albacore is a kind of tuna)
'cora abel cooked' is the wordplay.
'cooked' indicates anagramming the letters (letters cooked into a new form).
'cora'+'abel'='coraabel'
'coraabel' with letters rearranged gives 'ALBACORE'.
(Other definitions for albacore that I've seen before include "Variety of tuna" , "Large tuna; able orca (anag.)" , "fish" , "Long-fin tunny" .)