Sweet sauce from copper with celebrity daughter (7)
I believe the answer is:
custard
'sweet sauce' is the definition.
(I've seen this before)
'copper with celebrity daughter' is the wordplay.
'copper' becomes 'Cu' (chemical symbol).
'with' means one lot of letters go next to another.
'celebrity' becomes 'star' (I've seen this in another clue).
'daughter' becomes 'd' (genealogical abbreviation).
'cu'+'star'+'d'='CUSTARD'
'from' is the link.
(Other definitions for custard that I've seen before include "Cooked mixture of milk and eggs" , "Pudding sauce" , "Yellow sauce" , "Pudding accompaniment" , "Egg/milk bake" .)