Imam Ja'far al-Sadiq (a) has said, 
"My father, Imam al-Baqir (a) has said, In the first ten nights, between Salaat al- Magrib and ‘Isha, it is 
recommended to offer a two raka'at salaah. In each raka’at after Surah 
al-Fatihah recite Surah al-Tawhid once, and the verse below. (Q7:142)