Strange task, chore, for a biscuit (9)
I believe the answer is:
shortcake
'a biscuit' is the definition.
(shortcake is a kind of biscuit)
'strange task chore' is the wordplay.
'strange' indicates an anagram.
'task'+'chore'='taskchore'
'taskchore' with letters rearranged gives 'SHORTCAKE'.
'for' is the link.
(Other definitions for shortcake that I've seen before include "Rich biscuit; American dessert" , "Dessert from America" , "it crumbles!" , "pastry?" , "Rate shock (anag)" .)