Twice cook bird once (4)
I believe the answer is:
dodo
'bird once' is the definition.
'dodo' can be an answer for 'bird' (I've seen this before). I am not certain of the 'once' bit.
'twice cook' is the wordplay.
'twice' says to double the letters.
'cook' becomes 'do' (do can mean to cook).
'do' duplicated is 'DODO'.
Can you help me to learn more?
(Other definitions for dodo that I've seen before include "Extinct bird of Mauritius, very dead" , "bird long dead" , "Square" , "Proverbially extinct bird" , "Two rooks - one was unable to fly" .)