What promise did Babasaheb Tarkhad make to his son, and how did he end up breaking it?

To convince his son to travel to Shirdi, Babasaheb Tarkhad made a solemn promise. The account in Chapter 9 specifies that he assured his son, "Without offering Naivedya to Sai, no one should consume food at home." He vowed to perform the offering daily himself. However, he failed to keep this promise on one occasion. Being the chief officer of a large mill, his mind was preoccupied with business, and in his hurry, he completely forgot to offer the customary piece of sugar candy as Naivedya. Consequently, everyone in the household had their meals that day without the food first being dedicated to Sai Baba.