Riyad as-Salihin 728 — The Book About the Etiquette of Eating

A'isha Narrated from:

Messenger of Allah (ﷺ) said, "When any of you wants to eat, he should mention the Name of Allah in the beginning, (i.e., say Bismillah). If he forgets to do it in the beginning, he should say Bismillah awwalahu wa akhirahu (I begin with the Name of Allah at the beginning and at the end)." [At-Tirmidhi and Abu Dawud].