Excellent sort of pudding (4)
I believe the answer is:
plum
'sort of pudding' is the definition.
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for plum that I've seen before include "Fruit < that's highly desirable" , "Reddish-purple fruit" , "Shade" , "Dark-red fruit" , "excellent?" .)