From Sahih Muslim (Hadith 5319):
Anas b. Malik reported:Abu Talha ordered Umm Sulaim to prepare a meal specially for Allah's Apostle (ﷺ). He then sent me to him (to the Holy Prophet) ; the rest of the hadith is the same (but there is a slight variation of wording):" Allah's Messenger (ﷺ) placed his hand and mentioned the name of Allah upon that, and then said: Admit ten men. He (Abu Talha) admitted them and they got in. He (the Holy Prophet) said: Eat while mentioning the name of Allah upon it (the meal). They ate until eighty persons had taken the food. Then Allah's Apostle (ﷺ) had his meal and so the members of the household, and still they left some food
Reference: Muslim 5319