Impressive list of ingredients not about to rise (4)
I believe the answer is:
epic
'impressive' is the definition.
(I've seen this before)
I don't understand the remainder of the clue.
(Other definitions for epic that I've seen before include "Nonsense, rubbish" , "Blown up" , "Long story telling of a hero's deeds" , "long poem telling of heroic deeds" , "Long narrative poem telling of a hero's deeds" .)