A Schubert piece with heart (3)
I believe the answer is:
hub
'heart' is the definition.
(I know that hub is a type of heart)
'a schubert piece with' is the wordplay.
'with' indicates the answer is hidden within the clue.
'HUB' is hidden in the letters of 'schubert piece'.
(Other definitions for hub that I've seen before include "Centre (of network)" , "Nave of a wheel" , "Centre of wheel" , "Focal point of activity" , "Central part of a car wheel" .)