Soft, airy, and delicately sweet, this Japanese-style Castella sponge cake has a smooth crumb, a light golden crust, and a wonderfully soft texture. It needs no frosting or filling—just slice and enjoy with tea or coffee.
Why You’ll Love This Castella Cake
- Light and fluffy: Whipped egg whites give the cake its signature airy texture.
- Soft and moist: Milk and vegetable oil keep the crumb tender.
- Delicately sweet: Sweet enough to satisfy without being heavy.
- Golden crust: The top develops a beautiful, lightly caramelized finish.
- Simple and elegant: Perfect for tea time, brunch, gifting, or dessert.
Ingredients
- 6 large egg whites
- 6 large egg yolks
- 85 g sugar
- 80 ml vegetable oil
- 90 g cake flour
- 70 ml milk
- ¼ tsp salt
Instructions
1. Prepare the Meringue
Place the egg whites in a clean, dry bowl. Beat until foamy.
Gradually add the sugar while continuing to beat until the meringue forms stiff, glossy peaks.
2. Make the Batter
Warm the vegetable oil until hot but not boiling.
Sift the cake flour and salt into the warm oil. Mix until smooth.
Add the egg yolks and milk, then whisk gently until you have a smooth, lump-free batter.
3. Fold in the Meringue
Add about one-third of the meringue to the batter and mix gently to loosen it.
Add the remaining meringue in two additions. Fold gently with a spatula, taking care not to deflate the air.
4. Fill the Pan
Line a square or rectangular baking pan with parchment paper. Do not grease the sides.
Pour in the batter and gently tap the pan against the counter several times to remove large air bubbles.
5. Bake in a Water Bath
Place the cake pan inside a larger baking dish.
Pour hot water into the outer dish until it reaches about halfway up the sides of the cake pan.
Bake in a preheated oven at 150°C (300°F) for about 60 minutes, or until the center springs back when lightly touched and a toothpick inserted into the center comes out clean.
6. Cool and Slice
Once baked, gently tap the pan on the counter a few times to release excess steam and help prevent shrinking.
Allow the cake to cool completely in the pan.
Remove it from the pan and slice with a sharp serrated knife.
Tips for Perfect Castella Cake
- Use room-temperature eggs: They whip more easily and produce better volume.
- Keep the oil warm, not boiling: Excessive heat can affect the batter.
- Sift the flour: This helps create a smooth, light crumb.
- Fold gently: Overmixing can deflate the meringue and make the cake dense.
- Bake low and slow: The low temperature and water bath help prevent cracking and create an even texture.
- Avoid opening the oven: Sudden temperature changes can cause the cake to collapse.
- Let the cake cool gradually: Cooling too quickly can lead to shrinking.
Flavor Variations
Matcha Castella
Add 1 teaspoon sifted matcha powder to the flour for a subtle green-tea flavor.
Honey Castella
Replace 1 tablespoon of the sugar with honey for a deeper flavor and golden color.
Lemon Castella
Add 1 teaspoon finely grated lemon zest for a fresh citrus flavor.
Jam-Filled Castella
Slice the cooled cake horizontally and spread a thin layer of fruit jam or citrus marmalade between the layers.
Mini Castella Cakes
Bake the batter in small loaf pans or muffin molds. Reduce the baking time and check for doneness early.
Serving Suggestions
Castella is delicious on its own, but it also pairs beautifully with:
- Matcha latte
- Black coffee
- Milk tea
- Fresh berries
- Whipped cream
- Fresh fruit compote
For the best texture, serve the cake at room temperature.
Storage
Room temperature: Wrap the cooled cake tightly and store in an airtight container for up to 3 days.
Refrigerator: Keep well wrapped for up to 5 days. Bring to room temperature before serving.
Freezer: Slice the cake and wrap individual pieces well. Freeze for up to 1 month. Thaw at room temperature before serving.
Frequently Asked Questions
Why is my Castella cake not fluffy?
The meringue may have been under-whipped, over-whipped, or deflated during folding. Beat the egg whites until stiff, glossy peaks form and fold them gently into the batter.
Can I use all-purpose flour?
Yes. The cake may be slightly denser than when made with cake flour. For a closer texture, you can make a simple cake-flour substitute by replacing part of the all-purpose flour with cornstarch.
Can I skip the water bath?
A water bath is strongly recommended. The steam provides gentle, even heat and helps prevent cracking while keeping the cake moist and soft.
Why did my Castella cake collapse?
The cake may be underbaked, the meringue may have lost too much air, or the cake may have cooled too quickly. Make sure the center is fully baked and allow the cake to cool gradually.
Can I make Castella gluten-free?
Yes. Use a gluten-free cake flour blend suitable for sponge cakes. Results may vary depending on the flour blend.
Can I make it dairy-free?
Yes. Replace the milk with an unsweetened plant-based milk such as almond or soy milk.
What is the best knife for slicing Castella?
A sharp serrated knife works best. Wipe the blade clean between slices for neat, smooth edges.
Nutrition
Approximate nutrition per slice, based on 10 servings:
- Calories: 180
- Total Fat: 9 g
- Saturated Fat: 1 g
- Cholesterol: 105 mg
- Carbohydrates: 20 g
- Sugar: 11 g
- Protein: 5 g
- Fiber: 0.3 g
- Sodium: 80 mg