Hasan bin Ali was the one who most resembled the Messenger of Allah ﷺ in face.
حدثنا عبد الأعلى عن معمر عن الزهري
كان الحسن بن علي أشبههم وجها برسول الله ﷺ
No references are available.
Its isnad is sahih, and it is found in Abdul-Razzaq 3/335, no. 7980, in the chapter on aqiqah, what a child should be taught to say when he begins to speak.