Oldman after cooking finds nut (6)
I believe the answer is:
almond
'nut' is the definition.
(I know that almond is a type of edible nut)
'oldman after cooking' is the wordplay.
'after cooking' is an anagram indicator.
'oldman' is an anagram of 'ALMOND'.
'finds' is the link.
(Other definitions for almond that I've seen before include "Nutlike seed" , "Fruit for marzipan" , "Nut often used in cake icing (6)." , "Fruit kernel of a peach-related tree" , "Type of nut" .)