One repeats surprised comment about dessert (6)
I believe the answer is:
copier
'one repeats' is the definition.
(someone that repeats or copies)
'surprised comment about dessert' is the wordplay.
'surprised comment' becomes 'cor' (exclamation of surprise).
'about' means one lot of letters goes inside another.
'dessert' becomes 'pie' (pie is an example of a dessert).
'cor' going around 'pie' is 'COPIER'.
(Other definitions for copier that I've seen before include "Machine for making facsimiles" , "Office item" , "Reproducer" , "Machine for making duplicates" , "Office machine" .)