Fluffy Castella Sponge Cake Recipe

This fluffy Castella sponge cake is soft, moist, and delicately sweet, with a beautiful golden top and a fine, tender crumb. Made with simple ingredients and baked in a water bath, this Japanese-style sponge cake is perfect for afternoon tea, coffee breaks, or a light dessert.

Prep Time: 20 minutes
Cook Time: 60 minutes
Total Time: 1 hour 20 minutes
Servings: 10 slices
Oven Temperature: 300°F (150°C)

Ingredients

• 6 large eggs, separated
• 85 g granulated sugar
• 80 ml vegetable oil
• 90 g cake flour
• 70 ml milk
• ¼ teaspoon salt

Instructions

1. Prepare the Oven and Pan

Preheat the oven to 300°F (150°C). Line the bottom and sides of a square or rectangular cake pan with parchment paper. Avoid greasing the sides if you want the cake to rise evenly.

2. Prepare the Flour Mixture

Gently warm the vegetable oil until warm but not hot. Sift in the cake flour and salt, then whisk until smooth.

Add the egg yolks and milk. Mix until the batter is silky and free of lumps.

3. Whip the Egg Whites

In a clean, dry bowl, beat the egg whites until foamy. Gradually add the sugar while beating, then continue until glossy, firm peaks form.

4. Fold the Batter

Fold one-third of the meringue into the egg yolk mixture to lighten it. Gently fold in the remaining meringue in two additions, using a spatula to preserve as much air as possible.

5. Prepare the Water Bath

Pour the batter into the prepared pan and gently tap it on the counter to release large air bubbles.

Place the cake pan inside a larger baking dish. Carefully pour hot water into the outer dish until it reaches about halfway up the sides of the cake pan.

6. Bake

Bake for approximately 60 minutes, or until the top is golden and the center springs back gently when touched. A toothpick inserted into the center should come out clean.

7. Cool and Slice

Remove the cake from the water bath and let it cool gradually. Once completely cooled, lift it from the pan and slice with a sharp serrated knife.

Serve plain or with your favorite tea or coffee.

Tips for a Perfect Castella Sponge Cake

• Use room-temperature eggs: They help the batter combine smoothly and whip properly.
• Keep the bowl clean: Even a small amount of grease in the egg whites can prevent the meringue from reaching full volume.
• Warm the oil gently: It should be warm, not hot, before adding the flour.
• Sift the flour: This helps prevent lumps and creates a smoother crumb.
• Fold gently: Overmixing deflates the meringue and makes the cake dense.
• Use a water bath: Gentle, moist heat helps the cake bake evenly.
• Avoid opening the oven early: Sudden temperature changes can cause the cake to collapse.

Flavor Variations

• Matcha Castella: Add 1 teaspoon of sifted matcha powder to the flour.
• Honey Castella: Replace a small portion of the sugar with honey for a deeper sweetness.
• Lemon Castella: Add 1 teaspoon of finely grated lemon zest.
• Vanilla Castella: Add 1 teaspoon of vanilla extract to the egg yolk mixture.

Keep additions modest to preserve the cake’s delicate texture.

How to Serve Castella Cake

Castella cake is delicious on its own, but it also pairs well with:

• Green tea or matcha latte
• Black coffee or milk tea
• Fresh strawberries or other seasonal fruit
• Lightly sweetened whipped cream
• A small drizzle of honey

How to Store Castella Sponge Cake

Room temperature: Wrap the completely cooled cake and store in an airtight container for up to 2 days in a cool environment.

Refrigerator: Store tightly wrapped for up to 5 days. Bring it to room temperature before serving for a softer texture.

Freezer: Slice the cake, wrap each piece individually, and freeze for up to 1 month for best quality. Thaw before serving.

Castella Cake vs. Regular Sponge Cake

Frequently Asked Questions

Why isn’t my Castella cake fluffy?

The meringue may have been underwhipped or overwhipped, or the batter may have lost too much air during folding. Beat the egg whites until glossy, firm peaks form and fold them in gently.

Can I use all-purpose flour instead of cake flour?

Yes, but the texture may be slightly less tender. Cake flour is preferred for a finer, softer crumb.

Can I skip the water bath?

A water bath is recommended for this recipe because it provides gentle, even heat and helps prevent the cake from drying out or cracking.

Why did my cake collapse after baking?

A cake that is underbaked or cooled too quickly may collapse. Make sure the center is fully set and allow the cake to cool gradually.

Can I make mini Castella cakes?

Yes. Divide the batter among smaller lined pans and begin checking for doneness earlier, as smaller cakes bake faster. Use a suitable water bath if the pans allow it.

Can I make this cake dairy-free?

Yes. Replace the milk with an unsweetened plant-based alternative, such as soy or almond milk. The flavor and texture may change slightly.

Is Castella cake gluten-free?

The original recipe contains wheat flour. You can experiment with a suitable gluten-free cake flour blend, but the texture may differ.

What is the best way to cut Castella cake?

Use a sharp serrated knife and wipe the blade clean between slices for neat edges.

Final Thoughts

This fluffy Castella sponge cake is a beautiful example of how simple ingredients and careful technique can create a delicate homemade dessert. With its golden top, soft crumb, and subtle sweetness, it’s an excellent choice for tea time or whenever you want a light, elegant cake.

For the best results, whip the meringue carefully, fold gently, and bake slowly in a water bath.