Composition in which harp's played so extremely daintily (8)
I believe the answer is:
rhapsody
'composition' is the definition.
(I've seen this before)
'harp's played so extremely daintily' is the wordplay.
'played' indicates an anagram.
'extremely' suggests removing the centre.
'daintily' with its centre taken out is 'dy'.
'harp' is an anagram of 'rhap'.
'rhap'+'so'+'dy'='RHAPSODY'
'in which' acts as a link.
(Other definitions for rhapsody that I've seen before include "Expression of ecstatic enthusiasm" , "Ecstatic utterance" , "Ecstatic written or spoken statement" , "Exalted, free-style, composition" , "ecstatic words?" .)