Centre of target that's sweet (5-3)
I believe the answer is:
bulls-eye
I believe this clue is a double definition.
'centre of target' is the first definition.
(I've seen this before)
'sweet' is the second definition.
(I've seen this before)
'that's' acts as a link.
(Other definitions for bulls-eye that I've seen before include "Centre of the target (4'1, 3)" , "Window - sweet" , "The centre of a shooting target" , "The centre of the target, as in darts" , "Accurate shot" .)