Can you tell me the story of the Tarkhad family and the forgotten food offering? I heard it involved a promise to Sai Baba.

Certainly. The story from Chapter 9 describes the Tarkhad family's devotion. The son was a devout worshipper of Sai Baba's photograph and would not eat without first making a food offering, or Naivedya. When his mother wished to visit Shirdi, the son hesitated to leave, worried about who would continue the daily worship. His father, Babasaheb Tarkhad, promised to perform the ritual. For a time, he did so diligently, offering sugar candy. However, one day, preoccupied with business, he forgot. Realizing his mistake at mealtime, he was overcome with deep remorse, considering it a great sin. He prayed for forgiveness and wrote a letter to his son in Shirdi, asking him to plead with Sai on his behalf.