This recipe shows you how to make Nagasaki Castella, a traditional Japanese confection. Pour the batter—made by carefully mixing whipped egg whites and yolks, corn syrup, honey, and strong flour—into a mold lined with coarse sugar, and bake slowly in the oven. While the castella is still hot, wrap it in plastic wrap, place a weight on top, and let it rest overnight. This process results in a moist castella with a rich flavor. It's a perfect treat for entertaining guests or enjoying at home.