It's dished out in pieces (3)
I believe the answer is:
pie
'out in pieces' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'it's dished' is the wordplay.
I cannot really see how this works, but
'it' could be 'e' ('e' can mean 'electronic' which is similar to 'IT') and 'e' is found in the answer.
The remaining letters 'pi' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for pie that I've seen before include "Bird; pastry" , "Slapstick missile" , "Covered tart" , "what to cook for dinner?" , "In the sky, it's an unrealistic prospect" .)