Latin pastries I rejected - turned down a pile! (9)

'latin pastries' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.

'i rejected turned down a pile' is the wordplay.
'i' becomes 'me'.
'rejected' is a reversal indicator.
'turned' shows that the letters should be reversed in order.
'down' becomes 'sada' (I can't explain this - if you can you should give a lot more credence to this answer).
'a pile' becomes 'nap' (both can refer to the surface of a fabric).
'me' written backwards gives 'em'.
'sada'+'nap'='sadanap'
'sadanap' written backwards gives 'panadas'.
'em'+'panadas'='EMPANADAS'

Can you help me to learn more?