Castella is a popular sponge cake that originated in Portugal and is now widely enjoyed in Japan and other countries. It is known for its light, fluffy texture and sweet flavor, typically made with simple ingredients like eggs, sugar, flour, and honey. The cake is often baked in a rectangular shape and has a golden-brown crust. In Japan, Castella was introduced by Portuguese merchants in the 16th century and has since become a beloved dessert. It is commonly served in slices and can be found in various flavors, including matcha and chocolate. The cake is often enjoyed with tea or as a snack.