Champagne suppers are too much for her (5)
I believe the answer is:
agnes
'her' is the definition.
'champagne suppers are too much' is the wordplay.
'are too much' indicates the answer is hidden within the clue (the clue hides the answer plus unneeded letters).
'AGNES' can be found hidden inside 'champagne suppers'.
'for' is the link.
(Other definitions for agnes that I've seen before include "Girl's name" , "lass" , "Tube for cables" , "Scandinavian singer" , "David's second wife" .)