Composition in which harp plays so extremely daintily (8)
I believe the answer is:
rhapsody
'composition' is the definition.
(I know that rhapsody is a type of composition)
'harp plays so extremely daintily' is the wordplay.
'plays' indicates anagramming the letters.
'extremely' suggests removing the centre (only the extremes of the word are used).
'daintily' with its centre removed is 'dy'.
'harp' with letters rearranged gives 'rhap'.
'rhap'+'so'+'dy'='RHAPSODY'
'in which' acts as a link.
(Other definitions for rhapsody that I've seen before include "Exalted, free-style, composition" , "Ecstatic utterance" , "Ecstasy" , "Pretend to be what one is not" , "Gershwin wrote of one in blue" .)