Fancy sauce (6)
I believe the answer is:
relish
This clue is a double definition.
'fancy' is the first definition.
(thesaurus)
'sauce' is the second definition.
(I've seen this before)
(Other definitions for relish that I've seen before include "Salsa-like sauce" , "Pleasure - dressing" , "smack" , "Savour an experience" , "savoury stuff" .)