This as basis for the annual blow-out? (8,4)
I believe the answer is:
birthday cake
'this as basis for the annual blow-out?' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
This is the entire clue.
Can you help me to learn more?
(Other definitions for birthday cake that I've seen before include "Yearly confection" , "Anniversary fare" , "Celebratory confection" .)