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.
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.
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.
