Duck and ox meat I barbecued separately (3,2,1,4)
I believe the answer is:
one at a time
'separately' is the definition.
Both the answer and definition are adverbs. Perhaps there's an association between them I don't understand?
'duck and ox meat i barbecued' is the wordplay.
I cannot quite understand how this works, but
'duck' could be 'o' (resembles zero - 'duck' in cricket) and 'o' is present in the answer.
'and' could be 'n' (common abbreviation for 'and') and 'n' is present in the answer.
'i' could be 'me' and 'me' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for one at a time that I've seen before include "A-team, I note, travelling separately" , "Individually" , "Singly" .)