Messenger of Allah (pbuh) said:
“Whosoever performs 12 rakahs of salah on the 27th night of Rajab, recites Fatihah and a surah from Quran, gives salam in every two rakats and asks Allah (swt) for forgiveness reciting “Subhanallahi wa-lhamdulillahi wa la ilaha illallahu wa-llahu akbar ”100 times after salah and then sends salutations onto the Prophet 100 times, if he prays and also intends to fast in the morning, his prayers about whatever he wishes of this world or of the hereafter will be accepted unless he prays for a sin.” (Bayhaqi: Shuab al Iman: 3531; Suyuti: Kanz al-Ummal: 35170)
Prophet Muhammad said:
“Whosoever performs salah of two rakats, recites Fatihah and twenty times surah al Ikhlas, sends blessings on the Prophet ten times after salah and prays “Allahumma inni as’aluka bimushaahadati asraaril muhibbina wa bil-khalwatilleti khassasta biha sayyidal-mursalina hına asrarta bihi laylatas-sabi’I wal-ıshrina an tarhama qalbiya-l hazina wa tujiba da’wati ya akram-al akramin” surely Allah (swt) accepts his prayer, exalts his glory, has mercy on his supplication and revives his heart on the day that hearts die.” (Sheikh Abdulrahman al-Safoori: Nuzhat al-Majalis: 1/141)

Hasan Basri (ra) says:
“When it was the 27th of Rajab, Abdullah bin Abbas (ra) used to enter itikaf in the morning and kept praying (salah) till the karahat time before dhuhr prayer. After performing the last sunnah of dhuhr, he prayed four rakats of nafilah prayer and recited Fatihah, Falaq, Nas and three times surah al Qadr and 51 times surah al Ihklas. After that, he kept supplicating till the asr time and said “Messenger of Allah (pbuh) used to do so.” (Sheikh Abd Al-Qadir Al-Jilani: Al-Ghunya li-Talibi Tariq al-Haqq: 1/332)