Ibn Abi Mulaykah narrates from Sayyidah Umm Salamah (may Allah be pleased with her) that the recitation of the Prophet (peace and blessings be upon him) was like this: "'In the name of Allah, the Most Gracious, the Most Merciful' [Surah al-Fatihah: 1], 'All praise is for Allah, the Lord of the worlds' [Surah al-Fatihah: 2]", that is, he would recite each verse separately.
Amr bin Harun, who is not strong, also narrated it from Ibn Jurayj and added to it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2384