Savoury jelly used as a garnish (5)
I believe the answer is:
aspic
(Other definitions for aspic that I've seen before include "Savoury jelly for coating meat, eggs etc" , "Savoury relish" , "Ending of Marlowe's thriller" , "Savoury jelly for coating meats and eggs" , "Savoury jelly for meat or vegetable" .)