WHEN A FOOT INJURY ended Maggie Austin’s career as a professional ballerina, she found comfort in the kitchen, whipping up cakes with her father and, later, with some of the finest pastry chefs in the country, earning a reputation that landed her desserts on the Today show and in the White House. The ballet studio may seem like unorthodox training ground for a cake designer, yet Austin’s designs bear the hallmarks of a ballerina’s craft: artistry, precision, grace, and beauty. In her first book, Maggie Austin Cake: Artistry and Technique (Houghton Mifflin Harcourt, 2017), Austin guides readers through her process, showcasing ethereal cakes cloaked in sugar flowers so detailed and delicate, only a Sugar Plum Fairy could create them.…