Spock waited patiently for her turn to try Bill's hard work. By then, a line had formed after word spread that the winner was giving away free samples, not to mention the presentation itself was drawing more than enough attention on its own. If Spock was also curious about the baker in question, she didn't linger on the thought. Obviously she was here to try the winning cake. For ... science.
When she reached Bill, Spock offered a traditional Vulcan salute in greeting before she reached for a piece to try. Her facial expression revealed absolutely nothing, of course. She really needed to work on her people skills. "It is impressive," Spock commented at length, finally having finished the sample before stepping aside to allow the next person to try some. Then she activated her PADD in order to record the flavors she could readily identify, briefly pausing in order to scan what cake Bill had left. The festivities were certainly entertaining in a bizarre way (par for the course with humans), but Spock still considered all of this work.