Poulenc’s variation - ultimate in exquisite richness (8)
I believe the answer is:
opulence
'richness' is the definition.
(I've seen this before)
'poulenc's variation ultimate in exquisite' is the wordplay.
'variation' indicates anagramming the letters.
'ultimate in' suggests the final letters.
The last letter of 'exquisite' is 'e'.
'poulenc' anagrammed gives 'opulenc'.
'opulenc'+'e'='OPULENCE'
(Other definitions for opulence that I've seen before include "Luxuriousness" , "State of affluence and luxury" , "Open clue? (anag)" , "Profusion, luxury" , "State of affluence or richness" .)