Abu Hurairah (May Allah be pleased with him) reported:
The Messenger of Allah (ﷺ) recited in the two supererogatory Rak'ah of the Fajr prayer Surat Al-Kafirun (No. 109) [in the first Rak'ah], and Surat Al-Ikhlas (No. 112) [in the second Rak'ah].[Muslim]. (ES)
App reference (ES): Book 9, Hadith 118 (ES)
Arabic/English book reference (ES): Book 9, Hadith 1108 (ES)