Mixing hot treacle endlessly makes pudding (9)
I believe the answer is:
charlotte
'pudding' is the definition.
(I've seen this before)
'mixing hot treacle endlessly' is the wordplay.
'mixing' is an anagram indicator.
'endlessly' means to remove the last letter.
'hot'+'treacle'='hottreacle'
'hottreacle' with its last letter taken off is 'hottreacl'.
'hottreacl' is an anagram of 'CHARLOTTE'.
'makes' acts as a link.
(Other definitions for charlotte that I've seen before include "US city" , "Yorkshire novelist" , "... one of the Brontes" , "Dessert" , "associated with the Web?" .)