Riyad as-Salihin 815
'Aishah (May Allah be pleased with her) reported:
The Prophet (ﷺ) used to offer eleven Rak'ah of optional Salat (prayers) in the latter part of night. When it was about dawn, he would offer two short Rak'ah and then would lie down on his right side till the Mu'adhdhin (one who calls for prayer) would come to inform him that the congregation had gathered (for prayer). [Al-Bukhari and Muslim] .
وعن عائشة رضى الله عنها قالت‏:‏ كان النبي صلى الله عليه وسلم يصلى من الليل إحدى عشرا ركعة، فإذا طلع الفجر صلى ركعتين خفيفتين ، ثم اضطجع على شقه الأيمن حتى يجئ المؤذن فيؤذنه (‏‏(‏متفق عليه‏)‏‏)‏‏.‏  ‏‏