I read about a couple who came to Shirdi to offer khichdi. Can you explain the circumstances of their visit and how the offering was finally made?

Certainly. This story from Chapter 28 involves a devout couple; the wife was from Berhampur and her husband was an officer in the Post Department. The wife had a dream of Baba asking for khichdi, which inspired their pilgrimage to Shirdi from Akola. They stayed for two months, but for fourteen days, the wife was unable to make her special offering. On the fifteenth day, driven by her resolve, she brought the khichdi to the masjid at noon. She found that Baba was already having his meal behind a curtain. Unwilling to be deterred after her long journey, she boldly moved the curtain aside with her own hand and entered to fulfill her desire.