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.
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.
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.
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:
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.
Creative Castella Cake Twists
This cake is stunning in its simplicity, but here’s how I love to experiment with flavors without compromising texture:
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.
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.
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.
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.
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