The Prophet ﷺ used to take hold of me and Hasan and say, "O Allah, I love them both, so love them."Yahya said that al-Taymi said, "I used to narrate this hadith, but then some doubt entered me about it. I said to myself, 'I have been narrating this for such and such a time,' and then I found it written down in my own records."
حدثنا يحيى بن سعيد عن التيمي عن أبي عثمان
كان النبي ﷺ يأخذني والحسن فيقول اللهم إني أحبهما فأحبهما قال يحيى قال التيمي كنت أحدث به فدخلني منه فقلت أنا أحدث به منذ كذا وكذا فوجدته مكتوبا عندي
Its chain of transmission is sahih, mentioned previously in 21684.