After the trial, why does Miss Maudie bake a large cake and only two small ones?How does this make Jem feel?

In chapter 22 when Jem, Scout, and Dill arrive at Miss Maudie's house and there are only two small cakes, at first they believe that Miss Maudie has forgotten Dill. However, they "understand" when "she cut[s] from the big cake and g[ives] the slice to Jem."

Miss Maudie sees that Jem is old enough to grasp the meaning of what has happened at Tom Robinson's trial. She responds to this by serving him from a "grownup" cake and speaking about the trial with him in an adult manner. Jem is deeply discouraged about the outcome, and Miss Maudie explains that not everyone in Maycomb is corrupt--for example, it was "no accident" that Judge Taylor assigned Atticus to the case instead of the unexperienced public defender.