Sweet Perfection: The Art of Castella, Japan's Beloved Sponge Cake

by Nana Young

The word castella may sound like something from a Western kitchen, but this treat is 100% Japanese. Also called kasutera cake, this bouncy sponge cake is the ideal snack for tea ceremonies and the perfect hospitality gift. Join us as we explore the sweet world of Japanese castella.

Introduction to Castella

Japanese castella cake

Castella (or kasutera) is a popular Japanese sponge cake known for its fluffy texture and sweet flavor. Although originating from Portugal in the 16th century, castella is one of Japan’s most famous wagashi (traditional sweets). It falls under the category of sponge cakes, but its bouncy nature, fine texture, compactness, and soft crumbs stand out from traditional sponge cakes.

Japanese castella is made with a few simple ingredients, including sugar, mizuame (glutinous starch syrup), flour, eggs, and honey. Although it’s sold all over Japan, the cake is a specialty of Nagasaki City. People all over the country enjoy kasutera cake with tea or coffee. It’s often sold at confectionery shops, kissaten (tea-drinking shops), department stores, and konbini (convenience stores).

The History of Castella in Japan

The History of Castella in Japan

Castella was introduced to Japan by Portuguese traders in the 16th century. At the time, the city of Nagasaki on western Kyushu Island was the only port city available for foreign trade. Because the cake could last for months, foreign traders took it with them on their trip to Japan and ate it during their journey. The original version was called pão de Castela or “bread of Castile,” in reference to a kingdom in Spain. It contained eggs, milk, and wheat flour.

During the Edo period (1603–1868), sugar was an expensive commodity in Japan and had to be imported from foreign countries. This made castella a prestigious snack reserved for the wealthy. Nagasaki, however, had sugar in abundance due to their import trades. Hence, castella became one of the city’s specialties. Over the centuries, the original castella recipe has undergone several changes to better suit the tastes of dessert lovers in Japan. Today, it’s a beloved national treat available to people of all social and financial statuses.

What Makes Castella Unique?

Traditionally baked original recipe

If you believe you can tell what castella tastes like because of your experience with regular sponge cake, you’re in for a pleasant surprise. In terms of texture, castella is more delicate than other sponge cakes. It has light, moist crumbs with a bouncy texture that is more similar to bread crumbs.

Castella also contains honey and mizuame, which is a popular glutinous starch syrup used to give Japanese wagashi their moist texture. Also, it uses bread flour, unlike other sponge cakes. The preparation of the cake involves baking the ingredients in a traditional bottomless wooden mold, shaped like a square.

Castella Across the Seasons: Seasonal Varieties and Innovations

Castella Across the Seasons

In Japan, castella is adapted to various seasons through the introduction of seasonal ingredients. That way, people never get tired of enjoying the cake, as its flavors are constantly changing.

During the spring season, you'll find sakura-flavored castella cakes all across Japan. This dessert is infused with fresh cherry blossoms. In the summer, delicious peaches take over the show and regions like Nagasaki enjoy castella designed with in-season peaches.

When autumn comes in late September, you can expect to see lots of sweet potato castella sold in confectionery shops. This period also falls during the peak orange-picking season, and most shops offer castella flavored with the famous mikan oranges. In winter, strawberries are popular in the country, especially Aomori, and they’re often used to make different kinds of desserts, including kasutera.

Exploring the Many Flavors of Castella: From Traditional to Trendy

Exploring the Many Flavors of Castella

Castella’s greatest appeal lies in the wide variety of flavors and types you can enjoy. Some of them are available throughout the country, while others are regional specialty treats. Let’s explore the different types of castella cakes:

  • Matcha castella: This dessert is the most popular type of green tea castella. It involves mixing matcha powder with the other ingredients to make a bright and slightly bitter taste that complements the soft crumbs effectively.

  • Honey castella: This classic is arguably the most popular type of castella. It features all of the basic ingredients combined with a hearty flavoring of honey. Some variations exclude the use of mizuame. 

  • Cheese castella: The addition of cream cheese creates one of the softest types of castella cakes. 

  • Brown sugar castella: While most cake recipes use white sparkling sugar, the use of brown sugar in castella creates a caramel-like flavor and darker color.

  • Chocolate castella: The darker version of regular castella is popular in Western countries. It combines traditional ingredients with strong flavors of dark chocolate.

  • Baby castella: This bit-sized cake is popular at Japanese festivals. It does not have the iconic square shape but instead is small and round. .

  • Taiwanese castella: This variant originated in Taiwan, when the region was an annexed territory of Japan. It consists of a custardy center and a texture that closely resembles soufflé.

Castella cakes can also be used to make other Japanese wagashi. The most popular ones are basically castella cakes with unique fillings. They include dorayaki (with azuki bean paste filling) and siberia (with yokan or sweet bean jelly filling).

Celebrating with Castella: Its Role in Japanese Festivities

baby Castella close up

Baby castella is one of the most popular festival foods in Japan. These bite-sized sweet treats are sold in shops and served at picnics during these events. They may be flavored with different ingredients to match the season.

When castella was introduced to Japan, it was given as a gift and a peace offering. That tradition exists today, as Japanese people offer the cakes as gifts because they symbolize prosperity. People who travel also bring castella cakes from the regions they visit and omiyage (souvenir) items.

Where to Find the Best Castella in Japan

Where to Find the Best Castella in Japan

There are many top bakeries and shops in Japan known for their exceptional castella, particularly in Nagasaki, where the cake is most famous. The following are some of the best castella shops in Japan:

  • Bunmeido (Nagasaki): This shop offers what many consider the most delicious kasutera cakes in the world. They employ experienced craftsmen to make their treats by hand. 

  • Sho'oken (Nagasaki): This is the perfect spot for those who prefer cakes with less sugar. Their recipe tastes just as smooth as those of the other stores on our list.

  • Fukusaya (Nagasaki): The oldest castella shop in Japan, Fukusaya still offers delicious cakes even after so many years. Try their classic and chocolate flavors if you get the chance.

  • Tairaku Tangao (Tokyo): They sell the best Taiwanese castella cake in Tokyo. If you want extra fluffy cakes, this dessert restaurant is the spot to visit.

Pairing Castella: Serving Suggestions

Castella and Sencha

These cakes taste fantastic on their own, but you’ll love them more when you pair them with beverages. Tea and coffee remain the ideal pairing options. However, you could also enjoy the snack with some traditional Japanese drinks like sake and soy milk. The bitterness and earthy notes of green tea perfectly blend with the sweetness of the castella. We recommend matcha or sencha green tea. You could also try brown rice tea or twig tea.

Ice cream is another fantastic option. The creaminess of plain vanilla pairs well with the cake, but you will enjoy fruit-flavored ice cream and castella just as much. For a more natural accompaniment, pair it with actual fruits like strawberries, blueberries, and mangoes.

DIY Castella Baking Tips

DIY Castella Baking Tips

Castella may not be the easiest cake to bake, but it’s definitely not too difficult. To make it, mix sugar and egg yolks in a bowl, then add honey, mizuame, and flour. Pour the egg mixture into a baking pan or loaf pan lined with parchment paper and place it in an oven preheated to 170°C. In the first 12 minutes of the baking process, mix the batter four times and allow it to bake for 30 minutes more. Place the baked cake on a non-stick mat and allow it to cool. Next, encase it in plastic wrap for some hours. Your castella cake is ready to serve!

To ensure that you get the best results, remember the following tips and tricks:

  • Bread flour is the best flour to use. Other types, like all-purpose flour and cake flour, will not give you that authentic, bouncy, and even texture.

  • Wrinkles mean you have overbaked it. If the top of your cake starts to wrinkle, it means that you have left your cake in the oven for too long. Try to adjust the temperature next time.

  • Soggy cake has been underbaked. If you find your cake moist, soggy, and light in color, it means you didn’t cook it long enough.

  • Don’t overmix the batter. To avoid excess gluten formation after adding all the egg yolks, 30 seconds of mixing honey with the batter before transferring the egg yolk mixture to the cake pan is fine. 

Conclusion:

Castella, with its light and fluffy texture, remains one of the most popular desserts in Japan, especially during festivals. It would seem no one in the country can get enough of this simple, versatile, and symbolic treat.  

If you would like a taste of the iconic dessert, we recommend that you frequently check Bokksu Boutique for new Japanese castella cake products and other gift-worthy snacks from Asia. We have Nagasaki Castella: Earl Gray for lovers of the classic handmade snack. It comes infused with Earl Gray leaves. Green tea lovers can enjoy Nagasaki Premium Castella Cake Matcha, which offers a more sophisticated take on the treat. The Classic Castella Cake Gift Set, with three snack boxes from a reputable bakery in Japan called Suzakiya, offers both classic and matcha options, giving you maximum value for your money.


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