From Sahih Bukhari (Hadith 2557):
Narrated Abu Huraira:The Prophet (ﷺ) said, "When your servant brings your meals to you then if he does not let him sit and share the meals, then he should at least give him a mouthful or two mouthfuls of that meal or a meal or two meals, as he has prepared it
Reference: Bukhari 2557