Sachet occasionally filled with gold relish (5)
I believe the answer is:
sauce
'relish' is the definition.
(relish can mean a sauce or dressing)
'sachet occasionally filled with gold' is the wordplay.
'occasionally' indicates alternate letters (letters taken at regular intervals or occasions).
'filled with' indicates putting letters inside.
'gold' becomes 'Au' (Au is the chemical symbol for gold).
The alternating letters of 'sachet' are 'sce'.
'sce' enclosing 'au' is 'SAUCE'.
(Other definitions for sauce that I've seen before include "'Hunger is the best . . . . .'" , "Meal moistener" , "Meat dressing" , "Relish - impudence" , "''Hunger is good .....''" .)