As a chef who’s slightly obsessed with texture, I have to say this fluffy Castella sponge cake is the definition of soft perfection. Each slice has that signature bounce, an ultra smooth crumb, and a light sweetness that melts on the tongue. I make this when I want a cake that feels elegant yet humble, with no need for frosting or fillings just pure, pillowy satisfaction.
“Castella sponge cake is what clouds would taste like if you could slice them.” – @SoftBakeDreams
Why You’ll Fall in Love With This Castella Sponge
Originating from Japan and inspired by European sponge cakes, Castella (or kasutera) has a uniquely moist, fluffy texture that makes it stand apart from other sponges. The secret? It’s all in the meringue, water bath baking, and gentle folding and when done right, the result is unbeatable.
Feather light texture: Thanks to whipped egg whites and steam baking, every bite feels like air.
No butter or heavy fats: It’s made with oil and milk for softness without richness overload.
Subtly sweet flavor: Just enough sugar to feel indulgent, but never overwhelming.
Beautiful golden crust: The top bakes into a lightly caramelized layer, no extra topping needed.
Elegant enough for any table: From afternoon tea to light dessert, it’s always the right choice.
Fluffy Castella sponge cake with a golden crust sliced neatly on a wooden board
This light and airy Castella sponge cake is baked to golden perfection with a delicate crumb
Craving more melt in your mouth bakes? Try our pillowy Japanese cheesecake or the ultra soft milk brioche that bakes up just as light and satisfying.
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Step by Step Guide to a Perfect Fluffy Castella Cake
This cake may look delicate, but it’s very doable with a little care. Follow these steps exactly and you’ll get a perfectly risen, smooth topped sponge with no cracks or collapse.
Ingredients
6 egg whites
6 egg yolks
85 g sugar (superfine or caster is ideal)
80 ml vegetable oil
90 g cake flour or sponge flour
70 ml milk
¼ tsp salt
Instructions
1: Whip the Meringue
In a clean, dry bowl, beat the egg whites until they become foamy.
Gradually add sugar and continue whipping until stiff peaks form the meringue should be glossy and stable.
2: Prepare the Batter Base
Heat the oil for 90 seconds in the microwave or gently on the stove. It should be warm but not boiling.
Add sifted flour and salt into the warm oil and mix until smooth.
Stir in the egg yolks and milk, mixing until you have a silky, lump free batter.
3: Fold in the Meringue
Take one third of the meringue and gently mix it into the batter to loosen it.
Then, fold in the remaining meringue in two more additions, using a spatula and gentle motions to keep the batter airy.
4: Pour and Tap
Pour the batter into a parchment lined square or loaf tin (avoid greasing the sides).
Tap the tin on the counter several times to remove air bubbles that might cause holes during baking.
5: Water Bath Baking
Place the cake tin inside a larger baking dish and fill the outer dish with hot water halfway up the sides.
Bake in a preheated oven at 150°C (300°F) for about 60 minutes, or until the center springs back and a toothpick comes out clean.
6: Cool and Slice
When done, gently bang the tin on the counter a few times to release steam and prevent shrinking.
Let the cake cool completely in the tin, then transfer to a cutting board and slice with a serrated knife.
“The magic of Castella is in the details from how you fold the meringue to how you tap the tin. Every step matters.” – @SpongeWhisperer
Fluffy Castella sponge cake with a golden crust sliced neatly on a wooden board
This light and airy Castella sponge cake is baked to golden perfection with a delicate crumb
Pro Tips for Castella Success
Techniques That Make a Difference
This isn’t your average sponge cake the method is part of what gives Castella its signature bounce and cotton soft bite. Here are tips I follow every time:
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Use room temperature eggs: They whip better and give more volume.
Don’t overheat the oil: Just warm enough to blend the flour, but not hot enough to scramble the yolks.
Always sift your flour: Even a few lumps can weigh the cake down or cause streaks.
Fold, don’t stir: Keep your motions slow and careful to avoid deflating the airy meringue.
Bake low and slow: High heat causes cracking 150°C and steam creates that smooth, glossy top.
Need more steam based bakes? Check out our delicate milk custard rice cake or the beautifully jiggly Japanese cheesecake that uses a similar water bath method for texture that wows.
“With Castella, it’s not about speed it’s about softness. Let the batter breathe and the oven do its quiet work.” – @SlowBakeClub
Creative Castella Cake Twists
This cake is stunning in its simplicity, but here’s how I love to experiment with flavors without compromising texture:
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Matcha Castella: Add 1 teaspoon of sifted matcha powder with the flour for a subtle earthy twist.
Honey infused: Swap out 1 tablespoon of sugar for honey for a deeper golden crust and natural sweetness.
Lemon version: Add 1 teaspoon of lemon zest and a tiny splash of lemon juice for a bright finish.
Layered with jam: Slice the cake horizontally and add a thin spread of fruit jam or citrus marmalade between layers.
Mini Castella bites: Bake the batter in cupcake molds using the same water bath method for adorable, single serve treats.
Want more cake creativity? Our 3 ingredient sponge cake is perfect for fast flavor experimentation, and the Greek yogurt cake offers a rich but tangy spin on light cake recipes.
“You can change the flavor, but never the feel Castella must be soft, smooth, and born from patience.” – @FluffMasters
Perfect Pairings and Serving Suggestions
What to Serve With Fluffy Castella Sponge Cake
This sponge cake shines on its own, but pairing it with the right drink or side can turn it into a complete experience. Light, not overly sweet, and full of bounce, Castella complements a range of beverages and toppings.
Pairing Flavor Profile Why It Works
Matcha Latte Earthy and creamy Balances the soft sweetness with rich, roasted green tea
Black Coffee Bold and bitter Highlights the subtle sweetness of the sponge cake
Whipped Cream and Berries Light, sweet, and tart Adds color and flavor contrast without overwhelming the cake
Milk Tea Silky and slightly floral A popular Asian pairing that enhances the cake’s milky notes
Fresh Fruit Compote Sweet and syrupy Moistens the crumb while adding visual flair
Looking for other light desserts that pair perfectly with tea? Try our orange blender cake or the beloved pineapple quick bread for a sweet bite that still feels light.
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“Castella is never loud pair it with subtle, thoughtful flavors that let its softness speak.” – @ZenBakerMoments
Occasions Where Castella Cake Steals the Show
This cake isn’t just for special occasions it’s a staple you’ll want to serve any time you need comfort, calm, and class on a plate. Here’s where it shines most:
Afternoon tea or coffee time: Slice thinly and serve with your favorite warm drink for a relaxing break.
Elegant brunch spreads: Offer alongside pancakes, fruits, and soft cheeses.
Light birthday dessert: It’s a lovely alternative to heavy frosting cakes especially with fruit toppings.
Festive gifting: Bake in mini loaf pans and wrap in parchment for elegant edible gifts.
Cultural celebrations: Serve during Lunar New Year, tea ceremonies, or minimalist weddings.
“When you want your dessert to whisper elegance instead of shouting sweetness, Castella is the one.” – @SubtleSlices
Storage, Make Ahead, and Batch Baking Tips
How to Store Castella Cake Properly
The beauty of a good Castella sponge cake is that it actually improves in texture after resting. The cake becomes slightly denser and even more moist the day after baking making it perfect for advance preparation.
Room Temperature: Wrap the cooled cake tightly in parchment paper and plastic wrap. Store in an airtight container at room temperature for up to 3 days.
Refrigeration: For longer storage, refrigerate wrapped cake for up to 5 days. Bring to room temperature before serving to regain its soft texture.
Freezing: Slice the cake, wrap each piece in parchment and then plastic wrap. Freeze in a zip top bag for up to 1 month. Thaw slices at room temp before serving.
Want more freezer friendly baked goods? Try our crescent donuts or 10 minute skillet bread both hold up beautifully with make ahead prep.
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“With Castella, day two is even better store it right and let the flavors deepen overnight.” – @MakeAheadMagic
Batch Baking for Events and Gifting
Castella is a dream when baked in batches the cake slices cleanly, holds its shape, and offers an elegant presentation. Whether you’re preparing for a brunch spread, tea party, or gifting during holidays, here’s how to scale it smoothly:
Double the recipe: Use two baking tins and double all ingredients for 20 servings. Bake side by side and rotate halfway through for even browning.
Mini loaves: Divide the batter into mini loaf pans and reduce baking time to 25-30 minutes. These make wonderful gifts when wrapped in parchment and ribbon.
Individual cakes: Bake in muffin or cupcake pans using parchment sleeves. These single portions are great for dessert platters or lunchboxes.
Layer cake variation: Make two thin Castella cakes and sandwich them with whipped cream and fresh fruit for a light and airy celebration cake.
Looking for more gifting ideas? Our butter piped cookies and homemade crepes also travel well and bring smiles every time.
“Baking in batches? Castella is your secret weapon light, easy to portion, and always elegant.” – @BakeInBulk
Flavor Variations for Every Season
While traditional Castella is simple, you can easily switch it up by adding subtle ingredients that complement its soft structure. Here are seasonal inspired twists that work beautifully without altering the texture:
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Season Flavor Additions Serving Idea
Spring Matcha powder, lemon zest Serve with berries and fresh mint tea
Summer Orange zest, almond essence Top with citrus glaze and chilled cream
Autumn Pumpkin puree (2 tbsp), cinnamon Pair with chai or spiced tea
Winter Honey, nutmeg, vanilla bean Serve warm with a drizzle of caramel
Want a bright flavor twist? Don’t miss our Greek yogurt cake or zesty lemon cake for bakes that blend fruit and texture perfectly.
“Soft enough to absorb seasonal flavors, sturdy enough to hold its shape Castella adapts like a dream.” – @SeasonalSponge
Castella Sponge vs Other Sponge Cakes
Let’s take a moment to appreciate what makes Castella unique. Here’s a quick comparison of how this delicate sponge stands next to others in the sponge cake family:
Cake Type Main Ingredients Texture Best Use
Castella Eggs, sugar, flour, oil, milk Fluffy, moist, jiggly Tea time, gifting, light desserts
Basic Sponge Eggs, sugar, flour Light and airy, dry Layered cakes, rolls, filled desserts
Japanese Cheesecake Cream cheese, eggs, sugar, flour Jiggly, creamy, souffle like Special desserts, chilled servings
Eggless Vanilla Cake Flour, sugar, milk, oil Moist, dense, soft Quick bakes, dietary alternatives
Each has its charm, but Castella’s slow baked, water bath magic gives it that silky smooth finish that makes every bite feel delicate and delightful.
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“If sponge cake is poetry, Castella is a haiku brief, soft, and unforgettable.” – @MinimalistBakes
Calories and Nutrition (Per Serving – 1 Slice, Based on 10 Servings)
Calories: 180
Total Fat: 9g
Saturated Fat: 1g
Cholesterol: 105mg
Carbohydrates: 20g
Sugar: 11g
Protein: 5g
Fiber: 0.3g
Sodium: 80mg
“Just 180 calories of pillowy sweetness per slice this is the cake you enjoy with zero guilt and total pleasure.” – @SoftBakesOnly
Frequently Asked Questions About Castella Sponge Cake
Why is my Castella sponge not fluffy?
This usually happens if the meringue was over or under whipped, or if you folded too aggressively and lost air. Gently folding in stiff, glossy peaks is the key.
Can I use all purpose flour instead of cake flour?
Yes, but the texture will be slightly denser. For better results, substitute with a DIY cake flour (remove 2 tablespoons of flour per cup and replace with cornstarch).
What pan works best for Castella?
A square or rectangular nonstick pan lined with parchment is ideal. Avoid springform pans, as water baths can leak.
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Can I skip the water bath?
Not recommended. The steam helps prevent cracking, keeps the top glossy, and ensures even, gentle baking.
How do I store Castella sponge cake?
Wrap in plastic wrap and store at room temperature for up to 3 days. For longer storage, refrigerate for up to 5 days or freeze for 1 month.
What’s the best knife for cutting Castella?
Use a sharp serrated knife and wipe clean between slices to keep the edges smooth and prevent crumbling.
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Why did my cake collapse after baking?
This can happen if the cake is underbaked or if it’s cooled too quickly. Always do the toothpick test and let it cool slowly in the pan before unmolding.
Is Castella cake gluten free?
Not as written, but you can try a gluten free cake flour blend. Results may vary, so test in small batches first.
Can I make mini Castella cakes?
Absolutely! Use muffin molds or mini loaf pans and reduce baking time to 20-25 minutes. Still use the water bath method for best texture.
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Can I make this dairy free?
Yes, substitute the milk with unsweetened almond or soy milk. Texture remains similar, but flavor will change slightly.
“Every question about Castella has one answer gentleness. Handle every step with care, and the softness will follow.” – @CastellaCrafted
