بُلُوغُ الْمَرَامِ
Bulugh al-Maram 240
The Book of Prayer
وَعَنْ أَنَسٍ- رَضِيَ اَللَّهُ عَنْهُ- أَنَّ رَسُولَ اَللَّهِ - صلى الله عليه وسلم -قَالَ : { إِذَا قُدِّمَ اَلْعَشَاءُ فَابْدَءُوا بِهِ قَبْلَ أَنْ تُصَلُّوا اَلْمَغْرِبَ } مُتَّفَقٌ عَلَيْهِ . [1]
Narrated Anas (RA): Allah's Messenger (ﷺ) said: "If supper is brought (and the prayer is ready) start with it (the food) before you pray the Maghrib (prayer)." [Agreed upon].
Sunnah.com reference: Book 2, Hadith 108