Fluffy Castella Sponge Cake Recipe: How to Make the Perfect Japanese Sponge
When it comes to achieving a cloud-like, melt-in-your-mouth cake, nothing beats a classic Japanese Castella sponge cake. Known for its feather-light texture, glossy golden top, and moist crumb, this traditional treat is a celebration of simplicity, precision, and flavor. Whether you’re serving it with tea, gifting it for holidays, or simply craving an elegant bake, this fluffy Castella sponge cake is guaranteed to impress.
In this comprehensive guide, we walk you through everything you need to know—from ingredients and techniques to storage and seasonal variations—so you can master this timeless Japanese dessert with confidence.
🍰 What Makes Castella Sponge Cake So Special?
Originating in Japan and inspired by Portuguese Pão de Ló, Castella (Kasutera) is beloved for its:
- Silky, bouncy texture
- Moist, pillowy crumb
- Subtle sweetness that doesn’t overpower
- Golden, slightly caramelized top crust
- Elegant presentation with no frosting required
Unlike Western sponge cakes, Castella is baked in a water bath at a low temperature, using whipped egg whites (meringue) to create height and structure—without leavening agents.
🧾 Ingredients for the Best Castella Sponge Cake
Makes 1 loaf / 8–10 slices
- 6 large egg whites
- 6 large egg yolks
- 85g superfine or caster sugar (not granulated)
- 80ml vegetable oil (neutral oil like canola or sunflower)
- 90g cake flour, sifted (or use a low-protein flour)
- 70ml whole milk (room temperature)
- ¼ tsp salt
Note: Room temperature eggs whip better and produce more stable meringue.
👩🍳 Step-by-Step: How to Make Fluffy Castella Sponge Cake
Step 1: Prepare the Meringue
- In a large, grease-free mixing bowl, beat egg whites on medium speed until foamy.
- Slowly add sugar in small increments.
- Continue beating until stiff, glossy peaks form. Do not overbeat.
Your meringue should stand tall and shiny when you lift the whisk.
Step 2: Make the Batter Base
- In a separate bowl, warm the oil (not hot, just slightly warm to touch).
- Add sifted cake flour and salt to the oil and stir until smooth—no lumps.
- Add egg yolks and mix well.
- Pour in milk and whisk until the mixture is silky and lump-free.
Step 3: Fold the Meringue Into the Batter
- Add one-third of the meringue to the yolk mixture. Stir gently to loosen the batter.
- Carefully fold in the remaining meringue in two batches using a spatula.
- Use a gentle folding motion—scoop from the bottom, turn, and repeat. Do not stir vigorously.
Tip: Folding preserves the air bubbles that give the cake its signature rise and fluff.
Step 4: Pour, Tap, and Prepare for Water Bath
- Pour the batter into a lined loaf or square tin (avoid greasing the sides).
- Gently tap the pan on the counter 4–5 times to release any large air pockets.
Step 5: Bake with Steam (Water Bath Method)
- Place the cake tin inside a larger pan.
- Add hot water to the outer pan until it reaches halfway up the cake tin.
- Bake at 150°C (300°F) for 60 minutes, or until the top is golden and springs back.
A toothpick inserted should come out clean with no wet batter.
Step 6: Cool, Slice, and Serve
- Once baked, gently tap the tin on the counter to release trapped steam.
- Let the cake cool completely in the pan.
- Carefully remove, transfer to a cutting board, and slice using a sharp serrated knife.
Letting the cake rest overnight improves moisture and texture.
💡 Pro Tips for Castella Cake Success
- Use cake flour for the finest crumb. All-purpose flour will make the cake denser.
- Don’t overwhip the meringue—it should be firm, not dry.
- Always sift flour to avoid streaks or heaviness.
- Bake low and slow—Castella requires gentle heat for that smooth, shiny surface.
- Let it cool gradually—Rapid cooling can cause collapse or wrinkles.
🍵 Serving Suggestions for Castella Cake
Castella sponge cake is elegant on its own, but here are a few delightful ways to serve:
| Pairing | Flavor Profile | Why It Works |
|---|---|---|
| Matcha Latte | Earthy & creamy | Balances the cake’s sweetness |
| Black Coffee | Bold & bitter | Highlights the light flavor |
| Whipped Cream + Berries | Sweet & tart | Adds color and contrast |
| Milk Tea | Floral & silky | Classic Asian pairing |
| Fruit Compote | Juicy & bright | Moistens each bite beautifully |
🎨 Creative Variations on Classic Castella
Want to add a personal touch? Try these flavor infusions without compromising the structure:
- Matcha Castella: Add 1 tsp sifted matcha powder with the flour.
- Honey Castella: Replace 1 tbsp sugar with honey for a deeper crust.
- Lemon Zest: Add 1 tsp lemon zest + ½ tsp juice for a refreshing finish.
- Layered Jam Castella: Slice and add a thin layer of marmalade or fruit jam.
- Mini Bakes: Pour into muffin tins or mini loaf pans—reduce bake time to 25–30 minutes.
📦 Storage and Make-Ahead Tips
Castella cake gets even better after resting overnight. Here’s how to keep it fresh:
- Room Temperature: Wrap in parchment and store in an airtight container for up to 3 days.
- Refrigerator: Lasts 5 days—bring to room temp before serving.
- Freezer: Freeze slices in parchment and plastic wrap for up to 1 month.
Perfect for meal prep, brunch spreads, or gifting!
🎁 Batch Baking and Gifting Ideas
Need to make multiple cakes? Double the recipe and:
- Use two pans; rotate halfway for even baking.
- Bake in mini loaf pans for elegant edible gifts.
- Slice and wrap for lunchboxes, tea parties, or holidays.
This cake travels well and holds its shape—perfect for events and homemade gifts.
🌸 Castella Cake Through the Seasons
Customize your cake for any time of year:
| Season | Flavor Additions | Serving Suggestion |
|---|---|---|
| Spring | Matcha, lemon zest | Fresh mint & berries |
| Summer | Orange zest, almond extract | Citrus glaze |
| Autumn | Pumpkin puree, cinnamon | Warm chai pairing |
| Winter | Honey, vanilla, nutmeg | Caramel drizzle |
⚖️ Castella vs Other Sponge Cakes
| Cake Type | Texture | Best Use |
|---|---|---|
| Castella | Moist, jiggly, light | Gifting, tea time |
| Basic Sponge | Airy, dry | Layer cakes |
| Japanese Cheesecake | Creamy, souffle-like | Chilled desserts |
| Eggless Vanilla Cake | Dense, moist | Quick bakes, dietary needs |
📊 Nutrition (Per Slice – Based on 10 Servings)
- Calories: 180
- Total Fat: 9g
- Saturated Fat: 1g
- Cholesterol: 105mg
- Carbs: 20g
- Sugar: 11g
- Protein: 5g
- Sodium: 80mg
❓ Frequently Asked Questions
Why did my Castella collapse?
Likely underbaked or cooled too quickly. Always bake fully and cool slowly in the pan.
Can I use almond or soy milk?
Yes! Substitute 1:1, though the flavor will be slightly different.
Do I need a water bath?
Absolutely. It prevents cracking and creates a smooth top.
Can I freeze Castella cake?
Yes—slice, wrap tightly, and freeze for up to 1 month.
What knife should I use to slice it?
A sharp serrated knife wiped clean between cuts gives the best results.
Conclusion: Why Fluffy Castella Cake Belongs in Your Recipe Repertoire
This fluffy Castella sponge cake is a celebration of refined simplicity. With just a handful of ingredients and some care in technique, you’ll create a cake that feels luxurious, tastes light, and serves beautifully on any occasion. From tea time elegance