Flatten out gold beneath thin sheet of silver? (7)
I believe the answer is:
plateau
'flatten out' is the definition.
(I've seen this in another clue)
'gold beneath thin sheet of silver?' is the wordplay.
I cannot quite see how this works, but
'gold' could be 'au' (Au is the chemical symbol for gold) and 'au' is present in the answer.
'sheet' could be 'plate' (plate is a kind of sheet) and 'plate' is present in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for plateau that I've seen before include "High level land area" , "Area of flat, high ground" , "State of little change after a period of activity" , "Flat area of land" , "Flat highland" .)