In one of many memorable metaphors from Pie in the Sky, almost twelve-year-old narrator Jingwen recalls his favorite times with his family – rare Sunday beach trips when he and his younger brother, Yanghao, would collect seashells, giving them to their mother to hold, weighing down her pockets. Now, almost two years after the death of his father, and living in a new country with a new language to learn, Jingwen thinks of those seashells as problems, recognizing that his mother is already carrying the heavy weight of Yanghao’s seashells and her own. Struggling, but understanding, Jingwen thinks, "For now, I should try to carry my seashells in my own pockets."

It’s tempting to compare Lai’s masterful tale to a cake with many layers (like the rainbow cake that carries so much meaning for Lingwen), but her story is most like an onion with layers that peel away, ultimately revealing the central core of the story, the greatest burden that Lingwen carries with him throughout a challenging time. This sounds heavy, as the death of a parent in an middle grade novel often is, but Lai also manages, through her playful illustrations and the theme of baking that is the backbone of this novel, to be ultimately uplifting and hopeful in a story of growth and self-discovery, and (despite the title) CAKE.

Cakes are what brought about the disruptive changes in Jingwen’s life and baking cakes are what gradually gets him though it. Through her character building, descriptive writing and superb illustrations, Lai conveys the many powerful emotions that Jingwen experiences, most of which are initially expressed as anger and annoyance at his little brother (who, because of his age and mindset picks up English much faster and speaks the little he knows more confidently than his big brother) and alienation, fear  and isolation at not understanding the language spoken all around him. Early on, when Jingwen says he is on Mars, Lai’s illustrations morph the people around him into many-eyed and tentacled aliens, the words in their speech bubbles alternating between English (when Jingwen understands) and a language created by Lai. 

Jingwen’s complicated relationship with cakes – they are the center of happy celebrations as well as reminders of loss and sadness – is expressed throughout the novel as he persists in believing in their importance. There is the embarrassment of the "cheap," "plain" cakes that his father’s family’s bakery sells and the teasing Jingwen gets from his classmates (who bring fancy, colorful, character themed-cakes to school to celebrate their birthdays) as well as his gradual appreciation for Sundays spent making new cake recipes with his father in preparation for the bakery they would open in Australia and all that this move means for the future of his family. There are the traditional Chinese cakes made from "common, more affordable ingredients" that, as his father tells him, "fill up the tummies of people who are less well-off," and the complex cakes with rich ingredients that symbolize the hard work of Jingwen’s grand parents and parents and sacrifices made to give their children a opportunities that they did not have. Jingwen’s secret mission to make all twelve cakes that his father planned to sell at his Pie in the Sky bakery begins as a delicious distraction but grows into a dangerous, desperate venture that includes stealing money from his mother, almost burning down his apartment, and a pretty violent fight with his brother. The secret cake baking (and Jingwen and Yanghao’s hilarious attempts to eat all the evidence of their baking each night before their mother gets home from work) also turns out to be a way that Jingwen learns to speak English, gain a deeper understanding of his father, reconnect with a friend he hurt and, ultimately, tell his mother that he believes it’s his fault his father died.

Jingwen believes that cakes are magic and "cakes fix things." And, while a lot of things (and feelings) get broken over the course of the story, in the end -and especially with Papa’s rainbow cake, with his own addition of salty-sweet caramel sauce – Jingwen’s beliefs about cake prove true.