Empty, Charlie can eat cooked sea creature (8)
I believe the answer is:
cetacean
'sea creature' is the definition.
'empty charlie can eat cooked' is the wordplay.
'empty' means to remove the middle letters.
'cooked' indicates an anagram.
'charlie' with its middle removed is 'ce'.
'can'+'eat'='caneat'
'caneat' anagrammed gives 'tacean'.
'ce'+'tacean'='CETACEAN'
(Other definitions for cetacean that I've seen before include "Member of the animal order containing whales and dolphins" , "Generic name for whale, dolphin or porpoise" , "Animal order including whales and dolphins" , "Encase cat with mammals like whales and dolphins" , "Eg, whale, dolphin, etc" .)