Musnad Abu Ya'la al-Mawsili 159:72

And with his chain of narration, he said: The Messenger of Allah (ﷺ) said: "When one of you has his servant bring his food, and he has already spared him its heat and its preparation, then let him say: 'Sit and eat.' Or let him take for him from the food—and he gestured with his hand, meaning like this and like this—and let him place it in his palm, and let him say: 'Eat this.'"