Ummi Salamah Radiyallahu 'Anha reports:
"Rasulullah Sallallahu 'Alayhi Wasallam recited every aayah separately. He recited 'Alhamdulillaahi Rabbil 'Aa-lameen' and paused, then recited 'Ar Rahmaanir Raheem' and paused. Then paused after reciting 'Maaliki Yawmiddeen'" (ES)
English reference (ES): Book 43, Hadith 299 (ES)
Arabic reference (ES): Book 44, Hadith 316 (ES)