Could you recount the story from Chapter 23 about the Yoga practitioner who visited Sai Baba with Nanasaheb Chandorkar?

Certainly. Chapter 23 narrates the story of a practitioner of Yoga who, despite being well-versed in the Yoga Shastras, could not achieve Samadhi. Believing Sai Baba, the 'King of Yogis,' could help, he came for darshan with Nanasaheb Chandorkar. However, his faith wavered when he saw Baba eating stale bread with onions, and a strong doubt arose in his mind about Baba's spiritual stature. Being omniscient, Baba perceived this and remarked, "only those whose digestion is strong should eat onion." As Chapter 23 recounts, this statement startled the Yogi, who realized Baba knew his innermost thoughts. He then surrendered with true devotion, had his doubts resolved, and returned with a happy mind after receiving Udi and blessings.