Musannaf Ibn Abi Shayba 3:920

Abu Bakr narrated to us, he said: Sufyan ibn Uyaynah narrated to us, from al-Zuhri, from Urwah, from Aisha, she said: The Messenger of Allah (may Allah bless him and grant him peace) used to pray the Asr prayer while the sun was still high in my chamber. The shadow had not yet appeared.