The Book of Manners and Etiquette
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ نُمَيْرٍ، حَدَّثَنَا هِشَامٌ، - يَعْنِي ابْنَ عُرْوَةَ - عَنْ أَبِيهِ، عَنْ عَائِشَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ يُؤْتَى بِالصِّبْيَانِ فَيُبَرِّكُ عَلَيْهِمْ وَيُحَنِّكُهُمْ .A'isha reported that the new-born infants were brought to Allah's Messenger (ﷺ). He blessed them and rubbed their palates with dates
From Sahih Muslim, whose reports the scholars accept as authentic.