Castella Cake Recipe: Traditional Japanese Sponge Cake at Home

Castella cake, also known as kasutera, is a traditional Japanese sponge cake known for its light, fluffy, and incredibly moist texture. This homemade castella cake recipe is perfect for beginners who want to bake a soft, delicate dessert. Learn how to make this authentic sponge cake with step-by-step instructions.

What is Castella Cake?

Castella cake is a traditional sponge cake that originated in Japan during the Portuguese trade period. This elegant cake is perfect for tea parties, family gatherings, or any celebration. The cake's delicate flavor and soft crumb structure make it a favorite among cake lovers worldwide. Unlike heavy cakes, this light sponge cake is subtly sweet and incredibly moist.

Why You'll Love This Castella Cake Recipe

• Light and Airy Texture: The whipped egg whites create an incredibly fluffy interior
• Moist and Tender: Water bath baking keeps the cake soft and prevents drying
• Beginner-Friendly: Simple ingredients and easy-to-follow instructions
• Perfect for Any Occasion: Elegant enough for tea parties yet simple enough for family desserts
• No Frosting Needed: The cake's delicate flavor shines on its own

Castella Cake Recipe - Ingredients

For the Cake Batter:

• 80 g vegetable oil
• 115.5 g cake flour (low protein flour, 7-9% protein)
• 16.5 g cornstarch
• 99 g whole milk
• 8 large egg yolks
• 8 large egg whites (room temperature, cold)
• 99 g granulated sugar
• 2 g salt
• 2 tablespoons fresh lemon juice
• 2 tablespoons vanilla extract

For Baking:

• Parchment paper
• Aluminum foil
• Water for water bath

Castella Cake Recipe - Cooking Time & Equipment

Prep Time: 20 minutes | Cook Time: 65 minutes | Total Time: 1 hour 5 minutes

Cooking Temperature: 150°C (302°F)

Servings: 12 pieces

Difficulty Level: Beginner to Intermediate

Best Season: Year-round

Equipment Needed:

• 24×24×8 cm (9.5×9.5×3 inch) square springform pan
• Hand mixer or electric mixer
• Large mixing bowls (2-3)
• Measuring scale (grams recommended for accuracy)
• Rubber spatula
• Thermometer (optional but recommended)
• Wire cooling rack
• Large baking sheet or tray

Step-by-Step Castella Cake Recipe Instructions

Step 1: Prepare Your Ingredients & Preheat Oven

Preheat your oven to 150°C (302°F). Separate your eggs carefully—one at a time—ensuring no egg yolk gets into the egg white bowl. Any trace of yolk will prevent the whites from whipping properly.

Important Tips:

• Use a completely dry and clean bowl for egg whites (no water drops or grease)
• Separate eggs over a small bowl first, then transfer whites to the final bowl
• Keep the egg white bowl in the refrigerator until ready to use

Step 2: Heat the Vegetable Oil to Perfect Temperature

Heat vegetable oil to exactly 70°C (158°F). The best way to check temperature is using a kitchen thermometer. If you don't have one, heat the oil over medium-low heat for about 60 seconds until you see tiny bubbles forming at the bottom of the pan.

Temperature Tips:

• Don't overheat the oil—this will make your batter too thick
• Keep heat on low to medium-low
• Watch carefully for those first tiny bubbles

Step 3: Make the Egg Yolk Batter

Pour the warm oil into a dry, clean bowl. Add all dry ingredients (cake flour, cornstarch, and salt) and whisk until well combined. Add milk and mix until smooth. Finally, add egg yolks and mix well.

Mixing Guidelines:

• Mix until just combined—do not overmix
• Make sure no dry flour bits remain at the bottom of the bowl
• Use a spatula to scrape the bottom and check
• You can add vanilla extract here or in the next step with egg whites

Step 4: Whip the Egg Whites to Soft Peaks

Remove the egg white bowl from the refrigerator. Add lemon juice, granulated sugar, and vanilla extract to the cold egg whites. Using a hand mixer on medium-high speed, beat until soft peaks form. This should take 3-5 minutes.

Meringue Tips for Perfect Egg White Peaks:

• The meringue should be shiny and smooth
• You'll feel resistance when moving the mixer through it
• Peaks should hold their shape but slightly curl at the tips
• Stop beating when you reach soft peaks (don't overbeat to stiff peaks)
• Lemon juice and vanilla help reduce the eggy smell

Step 5: Fold Egg Whites into Batter Gently

This is the most critical step! Take one scoop of whipped egg white and gently fold it into the egg yolk batter until just combined. Then pour all remaining batter into the bowl with whipped egg whites and fold gently until just combined.

Folding Technique—VERY IMPORTANT:

• Use a rubber spatula with a gentle "cutting" motion
• Fold from the bottom up and over the top
• Do NOT stir, whisk, or overmix
• Overmixing deflates the egg whites and causes the cake to shrink
• Stop as soon as you see no streaks of white

Step 6: Prepare the Pan & Pour Batter

Line your 24×24×8 cm springform pan with parchment paper. Pour all batter into the pan and smooth the surface gently with a spatula.

Step 7: Water Bath Baking Setup

Wrap the bottom of your springform pan with aluminum foil to prevent water from seeping in. For extra protection, place a wire cooling rack on the bottom of a large baking sheet, then place the springform pan on top of the rack. This prevents the cake from touching the water directly.

Pour about 1 cm (½ inch) of room-temperature water into the baking sheet. Place the prepared springform pan into the water bath.

Water Bath Baking Tips:

• Leave space for the cake to rise in the oven
• Ensure enough water won't run out during the 65-minute bake time
• The water bath creates gentle, even heat for a moist cake

Step 8: Bake the Castella Cake

Place the water bath setup into your preheated 150°C (302°F) oven. Bake for 65 minutes until the cake is fully cooked. You can test doneness by inserting a toothpick—it should come out clean. If not, extend baking by 5-10 minutes.

Baking Tips:

• Don't open the oven door during the first 60 minutes
• The cake will rise and expand during baking
• Golden-brown color indicates the cake is almost done

Step 9: Cool the Cake Properly

Remove the cake from the oven and springform pan. Transfer it to a wire cooling rack and let cool completely. This prevents excess moisture from making the cake soggy.

How to Serve Castella Cake

Cut the cooled castella cake into thick, rectangular pieces. Serve plain to enjoy its delicate flavor and moist texture. For added elegance, dust with powdered sugar or drizzle lightly with honey. This cake pairs beautifully with green tea, black tea, or coffee.

Storage Instructions

Store leftover castella cake in an airtight container at room temperature for up to 2 days. For longer storage, wrap slices individually in plastic wrap and refrigerate for up to 5 days. You can also freeze castella cake for up to 1 month.

Nutrition Facts (Per Serving)

Servings: 12

• Calories: 187 kcal
• Total Fat: 10g (16% DV)
• Saturated Fat: 2g (10% DV)
• Cholesterol: 130mg (44% DV)
• Sodium: 66mg (3% DV)
• Total Carbohydrate: 18g (6% DV)
• Sugars: 9g
• Protein: 6g (12% DV)

Troubleshooting: Common Castella Cake Problems

Cake Shrinks During or After Baking: You likely overmixed the batter or deflated the egg whites. Fold gently and just until combined.

Cake is Dry: This happens when baked too long or at too high temperature. Stick to 150°C and 65 minutes exactly. The water bath is essential.

Cake Won't Rise: Your egg whites weren't whipped enough, or they were overbeaten. Aim for soft peaks.

Bottom is Too Moist: Remove from the springform pan immediately after baking to allow air circulation.

Eggy Smell/Taste: This is normal but add extra vanilla extract and lemon juice to reduce it.

FAQs About Castella Cake

Can I Use All-Purpose Flour Instead of Cake Flour? Not recommended. Cake flour (7-9% protein) creates the light texture. All-purpose flour will make it denser.

Do I Have to Use a Water Bath? Yes. The water bath is essential for the moist, tender crumb that makes castella cake special.

Can I Substitute Honey? You can try, but it affects the recipe's texture. Stick with granulated sugar for best results.

How Long Does Castella Cake Last? 2 days at room temperature, 5 days refrigerated, or 1 month frozen.

Conclusion

This traditional castella cake recipe creates a delicate, moist sponge cake perfect for any occasion. With careful attention to the folding technique and water bath baking, you'll achieve bakery-quality results at home. Try this easy castella cake recipe today and impress your family and friends with this elegant Japanese dessert!