Nut cracked for old man (6)
I believe the answer is:
almond
'nut' is the definition.
(almond is a type of nut)
'cracked for old man' is the wordplay.
'old man' anagrams to 'ALMOND'.
But, I'm not sure how the anagram is indicated.
Can you help me to learn more?
(Other definitions for almond that I've seen before include "Nut which provides cake icing" , "Old man with nice nut" , "Nut often used in cake icing (6)." , "Edible nut" , "Oval-shaped nut" .)