Compiled by Imam Yahya ibn Sharaf al-Nawawi
وعن كعب بن مالك رضى الله عنه قال: رأيت رسول الله صلى الله عليه وسلم يأكل بثلاث أصابع ، فإذا فرغ لعقها.((رواه مسلم))
I saw Messenger of Allah (ﷺ) eating with three fingers (i.e., the thumb, the index finger and the middle finger) and licking them after having finished the food.[Muslim].