Abu Dawud and at-Tirmidhi report something similar from 'Aishah (RA) that Allah's Messenger (ﷺ) used to recite a Surat in every Rak'at and in the last (third) Rak'at he would recite Qul Huwa Allahu Ahad (Surat al-Ikhlas) and al-Mu'awwidhatain.

وَلِأَبِي دَاوُدَ, وَاَلتِّرْمِذِيِّ نَحْوُهُ عَنْ عَائِشَةَ وَفِيهِ: { كُلَّ سُورَةٍ فِي رَكْعَةٍ, وَفِي اَلْأَخِيرَةِ:

قُلْ هُوَ اَللَّهُ أَحَدٌ

, وَالْمُعَوِّذَتَيْنِ } [1]‏ .‏