Sayyida Aisha (may Allah be pleased with her) said: The Messenger of Allah (peace and blessings be upon him) used to pray eleven rak‘ahs between ‘Isha and Fajr, and he would say salam after every two rak‘ahs and pray one rak‘ah as Witr.
Hadith Referenceسنن دارمي / من كتاب الصللاة / 1624