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What is Castella?
Castella (カステラ or kasutera) is a traditional Japanese sponge cake with over 400 years of history. The original version was first introduced by Portuguese merchants and Christian missionaries who arrived at the port of Nagasaki during the 16th century.
The defining characteristics of Castella cake are its smooth golden top, perfectly rectangular shape and intensely sweet flavor. It is also known for its texture, which is a beautiful balance of light and fluffy, yet moist and rich. This is achieved through the use of bread flour and whipped eggs, rather than using rising agents such as yeast or baking powder.
Castella is one of the most popular cakes in Japan and can be found in any supermarket or convenience store across the country. In my recipe I will show you how to make the best Castella at home, just like the ones you can get in Japan!
How I Developed This Recipe
My goal with this recipe, was to create a Castella that tastes just like the ones you can buy in speciality stores in Japan. Getting the right texture was particularly important here, and I wanted to achieve that without using complicated ingredients.
After experimenting with different sugar/honey quantities, egg yolk to egg white rations and even different mixing and baking methods, I’ve come to a result that I’m really proud of! I also added coarse sugar to the base for that perfect contrasting crunch!
If you want to try a perfectly sweet, moist and fluffy Castella cake, this is the recipe for you!
Key Ingredients & Substitution Ideas
To make Japanese Castella Cake, you will need the following ingredients:
- Eggs: Castella cake doesn’t contain any chemical rising agents like baking powder or baking soda. The rise is reliant on whipped egg whites, and a higher egg yolk ratio is used to create a rich flavor and bold yellow color.
- Flour: Traditional castella is typically made with bread flour to give it a stable and almost chewy texture, however I like to add a small amount of cake flour to give it a slightly lighter and fluffier texture.
- Sugar: Stick with white sugar for sweetness, caster or granulated both work fine. It is also typical to bake coarse sugar into the base for a crunchy texture. In Japanese, this sugar is known as “zarame”. Turbinado sugar is the best option for this as it doesn’t tend to melt when baked.
- Honey: Castella has a mild hint of honey flavor, the honey also adds moisture and a slight sticky texture. Although it’s not traditional, maple syrup is a suitable substitute.
- Milk and Oil: These liquids are added to soften the crumb and add moisture to the cake. Although melted butter can be substituted, the end result will be slightly drier.
Tools
- Electric whisk (to make meringue)
- 18cm square cake pan (two loaf pans can be used instead, but baking time will need to be adjusted)
- Baking paper (to line the cake pan)
- Airtight storage container (for cooling and retaining moisture)
Visual Walkthrough & Tips
Here are my step-by-step instructions for how to make Japanese Castella Cake at home. For ingredient quantities and simplified instructions, scroll down for the Printable Recipe Card below.
This section aims to provide a comprehensive overview of the cooking steps and techniques with visuals. I will also include more in-depth tips and tricks than the recipe card.
Start by measuring out all of your ingredients and bringing them to room temperature (about 20-30 minutes). This will help them combine more smoothly.
I also recommend separating the eggs straight from the refrigerator while they’re still cold to prevent the yolks breaking, but cover them and allow them to come to room temperature. Despite common belief, egg whites actually whip better at room temperature!
You can also use this time to line your cake pan with baking paper, and sprinkle the base with coarse sugar.
Before you begin, start heating your oven to 180°C (356°F).
Pour your egg whites in a clean, dry glass bowl. Any foreign objects (water droplets, oil, crumbs etc) can effect your meringue so a clean bowl is a must.
Whip the egg whites until foamy, then add the sugar one-third at a time. Wait until each third is well incorporated before adding the next, and whip until stiff peaks form.
The peaks should point upwards without folding over.
Use a low or medium speed on your whipper. It will take longer, but the air bubbles will be small, stable and less likely to pop or deflate. It’s tempting to use a high speed to save time, but this will create large air bubbles which can either pop or create large holes in your cake.
Add the yolks to the meringue one at a time and whip for 5-10 seconds to incorporate them.
Add the honey and whip for 5-10 seconds.
Sift the flour into a separate bowl to aerate it and break down any lumps.
Sift the flour again, this time into the egg mixture. Add it one-third at a time and use a silicone spatula or similar to gently fold it in.
Whisk the milk and vegetable oil together in a small bowl. Add 2-3 tbsp of the cake batter to the bowl and whisk until combined.
Pour the mixture over the spatula and into the batter, then carefully fold until combined.
The final batter should be thick and smooth.
Pour the batter into the lined cake pan and drop it on the counter to pop any large air bubbles. Use a wooden skewer to draw crosses both horizontally and vertically three times.
Place it on the top shelf and set a timer for 1 minute. Take the cake out and draw crosses horizontally and vertically again. Return to the oven for 1 minute, and repeat this step 3 times in total. This will help create a thicker crust on top.
After the final time, return to the top shelf and bake for 7 minutes.
Finally, reduce the heat to 160°C (320°F) and bake for another 30-40 minutes or until a skewer comes out clean.
Once the castella is cooked all the way through, carefully remove it from the cake pan and wrap it with plastic wrap while it’s still warm. This will help keep the moisture in the cake.
It also needs at least 12 hours (preferably 24 hours) of resting time before cutting, since castella is prone to drying out. Allowing it this resting time will ensure a deliciously moist castella cake.
Place it upside down in an airtight container and leave it until the next day. If it’s summer or you live in a warm climate, it is better to keep it refrigerated.
Once the cake has rested for 12-24 hours, trim the edges.
Cut it in half, then cut each half into thick slices about 2cm (3/4 inch) thick.
Tip: For clean cuts, use a sharp knife and wipe the blade between each slice!
How to Store
Homemade Castella Cake can be kept for 3-4 days in an airtight container in cooler weather, but in summer or warm climates it is better to keep it stored in an airtight container the refrigerator. This way it can be kept for up to 1 week.
To freeze Castella, it should be cut and wrapped individually with plastic wrap, then sealed in a freezer bag to prevent freezer burn. This method of storage will extend the life to 1 month.
Due to Castella’s high sugar content, it will not freeze completely so it can actually still be enjoyed frozen. However, if you would prefer to thaw it, you can microwave for 10-15 seconds to quickly defrost it, or thaw slowly in the refrigerator.
Storage Summary
Room temperature – 3-4 days (cooler climates, fall and winter)
Refrigerated – 1 week (warmer climates, spring and summer)
Frozen – Up to a month
I hope you enjoy this Japanese Castella recipe! If you try it out, I’d really appreciate it if you could spare a moment to let me know what you thought by giving a review and star rating in the comments below. It’s also helpful to share any adjustments you made to the recipe with our other readers. Thank you!
More Japanese Cake Recipes
Want more inspiration? Explore my Japanese Desserts Roundup Post for a carefully selected collection of tasty recipe ideas to satisfy your next sweets craving!
Japanese Castella Cake (Kasutera)
Equipment
Ingredients
- 1 tbsp coarse sugar turbinado or similar
- 100 g bread flour
- 20 g cake flour
- 3 egg whites
- 120 g caster sugar
- 4 egg yolk
- 40 g honey
- 30 ml whole milk
- 30 ml vegetable oil
Instructions
- Before you start, measure out your ingredients and separate the egg yolks and whites into separate bowls. Cover and allow to come to room temperature (this will help the ingredients incorporate more easily).
- Start preheating your oven to 180 °C (356 °F). Take a 18cm (7 inch) square cake pan and line it with baking paper slightly overlapping the edges (this will make it easier to pull out later). Sprinkle 1 tbsp coarse sugar across the baking paper and set aside for later.
- Sift the 100 g bread flour and 20 g cake flour into a bowl and set aside.
- Pour 3 egg whites into a clean, dry glass bowl and whip until foamy. Add 120 g caster sugar one-third at a time, making sure it's fully incorporated before adding the next third. Scrape down the sides of the bowl occasionally.
- Whip until you have a meringue with stiff peaks that stand up straight.
- Add 4 egg yolks one at a time and whip for 5-10 seconds each to incorporate.
- Drizzle 40 g honey into the meringue and whip for 10 more seconds before switching to a spatula.
- Sift the flour again, this time into the bowl of meringue. Add it one-third at a time and gently fold the mixture with a spatula to prevent losing too much air.
- In a small bowl, whisk 30 ml whole milk and 30 ml vegetable oil together. Add 2-3 tbsp of the cake mixture to the bowl and whisk them together until combined.
- Pour the mixture over a spatula and into the cake batter, then gently fold until combined.
- Pour the batter into the lined cake pan and use a bamboo skewer to draw lines across the surface, moving back and forth in a zigzag motion. Do this in both directions 3 times, then drop the pan on the counter to pop any large air bubbles. Place on the top shelf of the oven and bake for 1 minute.
- After one minute, take the cake out and draw lines in both directions again. Return to the top shelf and repeat twice more. After the third time, move the pan to the middle shelf and bake for 7 minutes. Reduce the heat to 160 °C (320 °F) and bake for another 30-40 minutes.
- The castella is done when a pierced skewer comes out clean. Once baked, drop on the counter to shock and prevent shrinking. Cool for a few minutes, then carefully pull it out of the pan.
- Wrap the whole castella cake with plastic wrap while it's still warm, then place it upside-down in a large airtight container and rest for 24 hours. If you live in a hot climate, refrigeration is recommended.
- After the resting period is up, unwrap the castella and trim the edges.
- Cut in half, then cut each half into thick slices. Use a sharp knife and wipe between each cut for a clean finish.
- Enjoy!
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