Christopher Kimball visits Cheryl Day at Back in the Day Bakery in Savannah, Georgia, to learn treasured recipes from her repertoire of southern baking. First, it's Sweet Potato Cupcakes with Cream Cheese-Caramel Frosting, where the buttery, bittersweet caramel brings out the earthiness and warm spices in the cupcakes. Then, they make a Glazed Sour Cream and Brown Sugar Bundt Cake, inspired by old-fashioned butterscotch candies. Finally, it's a grand, show-stopping Chocolate-on-Chocolate Three-Layer Cake.