As a chef who’s slightly obsessed with texture, I can tell you this Fluffy Castella Sponge Cake is the definition of soft perfection. Every slice boasts that signature bounce — a silky crumb that melts on your tongue with the most delicate sweetness.
It’s an elegant yet humble cake that needs no frosting, filling, or fancy garnish. Just pure, pillowy satisfaction.
💛 Why You’ll Fall in Love with Castella
Originating from Japan and inspired by European sponge cakes, Castella (Kasutera) is famous for its incredibly moist, airy texture and gentle sweetness. The secret lies in three techniques: a glossy meringue, slow steam baking, and careful folding — the trio that makes this cake cloud-soft.
- 🌥️ Feather-light texture: Whipped egg whites and steam baking create a sponge so airy it almost floats.
- 🧈 No butter or heavy fats: Made with oil and milk, it stays moist without feeling rich or greasy.
- 🍯 Delicate sweetness: Perfectly balanced — just enough sugar for indulgence without being cloying.
- ✨ Beautiful golden crust: A lightly caramelized top that looks and tastes exquisite — no topping needed.
- 🎂 Effortlessly elegant: Ideal for afternoon tea, brunch, or a light dessert that always feels special.
If you love tender, melt-in-your-mouth bakes, you’ll also adore our Japanese Cheesecake and Soft Milk Brioche — both share that dreamy, cloudlike texture.
🧁 Ingredients
- 6 egg whites
- 6 egg yolks
- 85 g (about ½ cup) superfine or caster sugar
- 80 ml vegetable oil
- 90 g cake or sponge flour
- 70 ml milk
- ¼ tsp salt
👩🍳 Step-by-Step Guide to the Perfect Castella
1. Whip the Meringue
- In a clean, grease-free bowl, beat egg whites until foamy.
- Gradually add sugar while beating until stiff, glossy peaks form. The meringue should hold its shape but remain silky.
2. Prepare the Batter Base
- Warm the oil for about 90 seconds in the microwave (or gently on the stove) — warm, not hot.
- Sift in the flour and salt; mix until smooth.
- Stir in the yolks and milk until you have a silky, lump-free batter.
3. Fold in the Meringue
- Start by folding one-third of the meringue into the batter to loosen it.
- Gently fold in the remaining meringue in two additions with a spatula, using light sweeping motions to keep the mixture airy.
4. Pour and Tap
- Pour the batter into a parchment-lined square or loaf tin (do not grease the sides).
- Tap the pan a few times on the counter to remove large air bubbles.
5. Water-Bath Bake
- Place the tin inside a larger baking dish and fill the outer dish halfway with hot water.
- 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
- After baking, lightly tap the pan on the counter to release steam and prevent shrinking.
- Cool completely in the pan before unmolding.
- Slice with a serrated knife for clean edges.
🌸 Pro Tips for Castella Success
- Use room-temperature eggs for maximum volume.
- Warm, not hot, oil — too hot and it can scramble the yolks.
- Always sift your flour for a fine crumb.
- Fold, don’t stir — slow, gentle motions keep the batter fluffy.
- Bake low and slow — the steam and gentle heat ensure a smooth top with no cracks.
Love soft, steam-baked desserts? Try our Milk Custard Rice Cake or the famously jiggly Japanese Cheesecake for another dose of delicate bliss.
🌿 Creative Castella Twists
- Matcha Castella: Add 1 tsp sifted matcha powder with the flour.
- Honey-Infused: Replace 1 tbsp of sugar with honey for a golden crust and deep flavor.
- Lemon Kissed: Add 1 tsp lemon zest and a splash of lemon juice for brightness.
- Layered Delight: Spread thin fruit jam or marmalade between slices for a tea-time treat.
- Mini Castella Bites: Bake in cupcake molds (20–25 min) using the same water-bath method.
☕ Perfect Pairings
| Pairing | Flavor Profile | Why It Works |
|---|---|---|
| Matcha Latte | Earthy & creamy | Balances the gentle sweetness with roasted green tea tones |
| Black Coffee | Bold & bitter | Highlights the subtle sugar and caramelized top |
| Whipped Cream & Berries | Light & tart | Adds color and freshness |
| Milk Tea | Silky & floral | Enhances the cake’s milky undertone |
| Fruit Compote | Sweet & syrupy | Adds moisture and shine |
🎉 Occasions Where Castella Shines
- Afternoon tea: Slice thinly for a refined snack.
- Elegant brunch: Serve with fruit and soft cheese.
- Light birthday cake: Top with whipped cream and fruit.
- Festive gifts: Bake in mini loaves and wrap in parchment.
- Cultural celebrations: Perfect for Lunar New Year or minimalist weddings.
🧊 Storage & Make-Ahead Tips
- Room Temperature: Wrap tightly in parchment and plastic wrap; store for up to 3 days.
- Refrigerate: Keeps up to 5 days; bring to room temp before serving.
- Freeze: Slice, wrap, and freeze for up to 1 month; thaw at room temperature.
Pro Tip: The flavor actually deepens after a day — making this an ideal make-ahead dessert.
🍰 Batch Baking & Gifting
- Double the recipe: Use two tins and bake side by side, rotating halfway for even browning.
- Mini loaves: Bake 25–30 minutes — perfect for gifting.
- Individual cakes: Use muffin cups for single-serve treats.
- Layer version: Bake two thin sheets and fill with whipped cream and fruit.
🌼 Seasonal Flavor Ideas
| Season | Flavor Additions | Serving Idea |
|---|---|---|
| Spring | Matcha, lemon zest | Serve with berries & mint tea |
| Summer | Orange zest, almond essence | Add citrus glaze & chilled cream |
| Autumn | Pumpkin purée, cinnamon | Pair with chai tea |
| Winter | Honey, nutmeg, vanilla | Serve warm with caramel drizzle |
🎂 Castella vs Other Sponge Cakes
| Cake Type | Main Ingredients | Texture | Best Use |
|---|---|---|---|
| Castella | Eggs, sugar, flour, oil, milk | Moist, fluffy, jiggly | Tea time, gifting |
| Basic Sponge | Eggs, sugar, flour | Light, dry | Layered cakes |
| Japanese Cheesecake | Cream cheese, eggs, sugar, flour | Creamy, soufflé-like | Special desserts |
| Eggless Vanilla Cake | Flour, sugar, milk, oil | Dense, soft | Quick bakes |
“If sponge cake is poetry, Castella is a haiku — brief, soft, and unforgettable.” 💭
⚖️ Nutrition (Per Slice – 1 of 10 Servings)
- Calories: 180
- Fat: 9 g
- Saturated Fat: 1 g
- Cholesterol: 105 mg
- Carbohydrates: 20 g
- Sugar: 11 g
- Protein: 5 g
- Sodium: 80 mg
❓ FAQs
Why isn’t my Castella fluffy?
Your meringue may have been under- or over-whipped, or over-mixed into the batter. Use stiff, glossy peaks and fold gently.
Can I use all-purpose flour?
Yes, but the texture will be slightly denser. To mimic cake flour, replace 2 tbsp of flour per cup with cornstarch.
Do I really need a water bath?
Absolutely. It keeps the cake moist, prevents cracking, and gives that smooth top.
Why did my cake collapse?
It may be underbaked or cooled too quickly. Always test doneness and cool slowly in the pan.
Can I make it dairy-free?
Yes — replace milk with almond or soy milk for a light variation.
Best knife for slicing?
Use a sharp serrated knife, wiping between cuts for clean edges.
💫 Conclusion
This Fluffy Japanese Castella Sponge Cake is softness perfected — a cloud-light, melt-in-the-mouth sponge that feels both nostalgic and luxurious. Its simplicity, combined with that delicate sweetness, makes it a timeless classic worth mastering.
Whether for tea time, celebrations, or gifting, this Castella will always rise (beautifully) to the occasion. ☁️🍰
