The original American restaurant (6)
I believe the answer is:
indian
'the original american' is the definition.
'indian' can be an answer for 'american' (Indian is an example). I am unsure of the 'the original' bit.
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for indian that I've seen before include "Eg, native of Mumbai" , "Of a subcontinent in Asia" , "One type of elephant" , "Relating to native of Bombay, say" , "IDA inn provides for this nationality" .)