Sayyiduna Abu Ayyub (may Allah be pleased with him) said: the Messenger of Allah (peace and blessings be upon him) prayed three rak'ahs of Maghrib and two rak'ahs of Isha at Muzdalifah with a single iqamah.
Hadith Referenceالمعجم الكبير للطبراني / باب الخاء / 3855