Finish off light fluffy dessert also known as a Greek favourite (8)
I believe the answer is:
moussaka
'a greek favourite' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'finish off light fluffy dessert also known as' is the wordplay.
I cannot really see how this works, but
'also known as' could be 'aka' ('a.k.a.' can be a synonym of 'also known as') and 'aka' is located in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for moussaka that I've seen before include "Greek dish of mince layers, aubergine and cheese sauce" , "Greek dish of lamb and aubergine" , "Greek dish of minced lamb, aubergines, etc" , "main course in Greece" , "Greek aubergine-based dish" .)