Sunan an-Nasa'i, Hadith 853 ⓘ
It was narrated that Anas said: "The Messenger of Allah said: 'If dinner is ready and the Iqamah for prayer is said, then start with dinner first."'
أَخْبَرَنَا مُحَمَّدُ بْنُ مَنْصُورٍ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنِ الزُّهْرِيِّ، عَنْ أَنَسٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِذَا حَضَرَ الْعَشَاءُ وَأُقِيمَتِ الصَّلاَةُ فَابْدَءُوا بِالْعَشَاءِ " .
also referenced under: Book 10, Hadith 77 (In-Book) & Volume 1, Book 10, Hadith 854 (DarusSalam)