Abu Ma'mar reported: There was an Amir in Makkah who pronounced taslim twice. 'Abdullah said: Where did he get this sunnah? Al-Hakam said: There is a hadith to the effect that the Messenger of Allah (ﷺ) did like It.
Hadith Referenceصحيح مسلم / كتاب المساجد ومواضع الصلاة / 581
'Amir bin Sa'd reported: I saw the Messenger of Allah (ﷺ) (may peace be open him) pronouncing taslim on his right and on his left till I saw the whiteness of his cheek.
Hadith Referenceصحيح مسلم / كتاب المساجد ومواضع الصلاة / 582