This article provides a recipe for making Castella, a soft and fluffy sponge cake, without using an oven. The author shares a step-by-step guide for creating this popular Japanese dessert using a pot instead. The recipe begins with mixing flour, sugar, and baking powder in one bowl. In a separate bowl, the author combines eggs, honey, and milk, and then incorporates the dry ingredients into the wet mixture. The batter is then strained to remove any lumps. The author explains that using a pot with a tight-fitting lid creates a steaming effect, mimicking the baking process of an oven. The pot is filled with water and a steamer rack is placed inside.