Castella: Nagasaki's Portuguese-Rooted Sponge Cake

Castella arrived in Nagasaki with Portuguese traders and missionaries in the 16th century, during the narrow window when Nagasaki was one of Japan's only ports open to European contact. The original recipe — flour, eggs, sugar, and starch syrup, baked without butter or oil — was adapted over centuries by Japanese confectioners into something distinct from its Iberian ancestor (pão de Castela). It's now firmly a Nagasaki specialty rather than a foreign import, sold in blocks and sliced to order.

Good castella has a dense but moist, spongy crumb and a layer of coarse sugar crystals settled at the bottom from baking — texture and that sugar layer are what separates a well-made one from a mass-produced version. It keeps well, which made it a practical souvenir long before that became the main reason people buy it. Plain is traditional, though matcha, chocolate, and other modern variations are widely sold alongside it now.