Money we return to this nut! (6)
I believe the answer is:
cashew
'this nut' is the definition.
(cashew is a kind of nut)
'money we return' is the wordplay.
'money' becomes 'cash' (cash is a type of money).
'return' says the letters should be written in reverse.
'we' back-to-front is 'ew'.
'cash'+'ew'='CASHEW'
'to' acts as a link.
(Other definitions for cashew that I've seen before include "nut-tree" , "snack perhaps" , "Acajou" , "Common type of nut" , "Kidney-shaped nut of tropical tree" .)