Also why does Duolingo use mi rather than mie?
"mi" is the official spelling.
Searching for "mie" in the KBBI returns no results....
"mie" is used in everyday speech and is also used as part of the name of the largest brand of instant noodles (Indomie).
It's an imperative sentence, a command.
(Kamu !) Buatkan saya mi ayam !
(You !) Make me chicken noodles !
'Buat mi ayam !'
'Bikin mi ayam !'
'- kan' suffix has a benefactive function with this verb.
Without "for me" , there is no beneficiary, so there is no need to use '-kan' suffix.
'bikin' = 'buat' = 'to make'.
'bikin' is less formal and frequently used in daily speech.