As salamu aleykum, I did read somewhere that the Prophet (SAW) sometimes used to make taslim once; Sometimes, "he would salute once only, [ As salamu aleykum ] [Peace be on you] in front of his face, turning to his right side a bit, [or a little]. Is this correct? Please quote the hadeeth which proves this.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

'Aa'ishah narrated that the Prophet used to say Tasleem once while facing straight and leaning slightly to the right side. [Al-Haakim and At-Tirmithi]

Al-Haakim classified this narration to be authentic according to the conditions set by Al-Bukhari and Muslim and Ath-Thahabi is of the same view. In addition to this, Al-Albaani classified it as authentic. This narration proves that it is permissible to conclude the prayer with one Tasleem.

This narration is the same as that narrated by Anas that the Prophet used to conclude the prayer with one Tasleem. [At-Tabaraani, and Al-Albaani classified it as authentic.] 

The majority of the scholars are of the view that it is acceptable to conclude the prayer with one Tasleem based on these two narrations.

However, in general, the Prophet used to conclude the prayer saying Tasleem twice, one to his right hand side and one to his left hand side. Sa'd said: "I used to see the Prophet saying Tasleem to his right hand side and to his left hand side until I could see the whiteness of his cheek [while performing the prayer behind him]." [Ahmad, Muslim, An-Nasaa'i and others]