Could you recount the story from Chapter 23 involving the Yoga practitioner who came for Baba's darshan?

Certainly. Chapter 23 tells the story of a practitioner of Yoga who, despite being well-versed in the Yoga Shastras, could not achieve Samadhi. Hoping Sai Baba, the King of Yogis, could help, he came to the Masjid with Nanasaheb Chandorkar. However, upon seeing Baba eating stale bread with onions, a strong doubt arose in his mind about Baba's spiritual stature. Being omniscient, Sai Baba immediately addressed his unspoken thought by remarking that only those with strong digestion should eat onions. This comment startled the Yogi, who realized Baba knew his inner thoughts. He then surrendered with true devotion, his doubts were resolved, and he returned with a happy mind after receiving Udi and blessings.