Hadith 1127 Ibn `Umar (Radhi Allahu Huma) reported: The Prophet
would not perform any Salat (in the Masjid) after the Friday prayer till he had returned to his house. He would then perform two Rak`ah there.[Muslim].
Commentary: In one Hadith, there is mention of four Rak`ah, while in the other it is mentioned as two Rak`ah. It can be deduced that both of these are acceptable. `Ulama' are of the opinion that one who performs them in the Masjid, should perform four Rak`ah; whereas the one performing them at home, should perform two Rak`ah with one Taslim. It is better to perform them in twos as the Prophet
is reported to have said,
"Perform the Nawafil of the day and night in twos.'' (Al-Bukhari).
For an explanation of this Hadith by Dr Muhammad Salah view the video included in Chapter 202