Forgetting the Doa before eating

بِسْمِ اللَّهِ أَوَّلَهُ وَآخِرَهُ

Bismillahi awwalahuu wa-aakhirahu

In the name of Allah, at its beginning and at its end.

Sunan Abi Dawud 3767; Jami' at-Tirmidhi 1858