It is narrated with this chain of narration, from 'Aishah who said:

"The Prophet (ﷺ) was eating food with six of his Companions. A Bedouin came and ate it in two mouthfuls. So the Messenger of Allah (ﷺ) said: "As for him, had he mentioned (Allah's Name), it would have been enough for all of you." [Abu 'Eisa said:] This Hadith is Hasan Sahih. Umm Kulthum is the daughter of Muhammad bin Abi Bakr As-Siddiq, may Allah be pleased with them.

وَبِهَذَا الإِسْنَادِ عَنْ عَائِشَةَ، قَالَتْ كَانَ النَّبِيُّ صلى الله عليه وسلم يَأْكُلُ طَعَامًا فِي سِتَّةٍ مِنْ أَصْحَابِهِ فَجَاءَ أَعْرَابِيٌّ فَأَكَلَهُ بِلُقْمَتَيْنِ فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏

‏ أَمَا إِنَّهُ لَوْ سَمَّى لَكَفَاكُمْ ‏

‏ ‏.‏ قَالَ أَبُو عِيسَى هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ ‏.‏ وَأُمُّ كُلْثُومٍ هِيَ بِنْتُ مُحَمَّدِ بْنِ أَبِي بَكْرٍ الصِّدِّيقِ رَضِيَ اللَّهُ عَنْهُ ‏.‏