One egg per year! (6)
I believe the answer is:
easter
'year' is the definition.
The definition and answer can be both related to time as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'one egg per' is the wordplay.
I cannot quite see how this works, but
'one' could be 'a' and 'a' is found within the answer.
The remaining letters 'ester' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for easter that I've seen before include "Monday of 1916 Rising" , "Time to celebrate" , "Christian festival in Spring" , "Important Christian festival" , "A steer (anag.)" .)