Can you tell me the story of how Sai Baba satisfied Laxmichand's craving for a specific sweet?

Certainly. The story from the Shri Sai Satcharitra details how Laxmichand and other devotees were visiting Shirdi. On the first day, they received a sweet called khaja as prasad. Laxmichand enjoyed it but missed it the following day. On the third day, in a remarkable display of omniscience, Sai Baba specifically ordered a devotee to bring a plate full of khaja as a food offering (naivedya). As Chapter 28 explains, this fulfilled Laxmichand's unexpressed desire. Later, at mealtime, khaja was served, and Laxmichand's attachment was fulfilled, filling his heart with joy and solidifying his devotion to Baba.