Like a layer of wood (5)
I believe the answer is:
ashen
'wood' is the definition.
Both the answer and definition are adjectives. Perhaps you can see a link between them that I can't see?
'like a layer' is the wordplay.
'like' becomes 'as'.
'a layer' becomes 'hen' (something which lays - eggs in this case).
'as'+'hen'='ASHEN'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for ashen that I've seen before include "White" , "Greyish" , "White-faced" , "Pale in complexion" , "of Tree" .)