Light, airy, and subtly sweet, Castella Cake is a delicate Japanese sponge known for its custard-like softness and springy crumb. Its simplicity hides a remarkable sophistication—soft edges, a golden top, and a whisper of honey in every bite. This elegant loaf makes a beautiful centerpiece for teatime or gifting, with a texture that only improves the longer it rests.
Ingredient Breakdown
The success of this cake begins with temperature. Room-temperature eggs are essential for structure and lift. When whipped, they expand with air to form the foundation of the batter. Cold eggs simply won’t aerate the same way, resulting in a flatter, less tender crumb.
Granulated sugar is more than sweetness—it stabilizes the whipped eggs. As the eggs foam, sugar dissolves and locks in the air, creating a batter that is sturdy yet light. This balance between stability and softness is crucial for Castella’s pillowy interior.
The honey and warm water mixture lends subtle floral notes and helps retain moisture. Honey acts as both a sweetener and a humectant, drawing moisture into the cake, which ensures that the texture stays supple even after a day or two.
Vanilla extract adds a final layer of complexity. It brings warmth and depth to an otherwise delicate flavor profile. Though subtle, it completes the cake’s aromatic signature, making every bite memorable.
Cake flour is key to the soft, cloud-like texture. With lower protein than all-purpose flour, it produces a finer, more delicate crumb. Anything heavier would weigh the batter down and compromise the cake’s gentle lift.
Salt—just a whisper—is there to balance the sweetness. It’s the quiet hero that heightens every other flavor, from honey to vanilla, adding clarity without ever making itself known.
Step-by-Step Preparation Guide
To prepare the pan, use a metal 8×8-inch square and line it with parchment that climbs at least an inch above the edges. This gives the batter room to rise gracefully without spilling over. Lightly coat it with nonstick spray to keep the parchment in place and ensure an easy release.
Begin by whipping the eggs and sugar on high until the mixture turns pale, thick, and voluminous. This takes around 6 to 8 minutes and results in a glossy, custard-like batter that can hold soft peaks and leaves trails when the whisk is lifted.
Next, gently fold in the honey mixture. It should be added slowly, on low speed, to avoid collapsing the air structure. The warm water helps keep the consistency smooth and prevents any ingredients from seizing up.
Sift the cake flour directly into the bowl in small additions. Fold it in gradually, using a gentle hand or keeping the mixer on its lowest setting. Overmixing at this stage will deflate the foam, so work just until the flour is fully incorporated.
After pouring the batter into the pan, give it a gentle tap or two on the counter. This brings larger air bubbles to the top without significantly deflating the overall structure. Be cautious—too much tapping can undo all your aeration.
Place the pan in the center of the oven and bake at 315°F for about 45 minutes. The top should rise into a subtle dome and darken to a deep, golden brown. A perfectly baked Castella will have a tender center with a slightly chewy top layer.
Immediately after baking, lift the cake from the pan using the parchment paper. Carefully peel it away, then wrap the warm cake tightly in plastic wrap. This locks in steam, keeping the interior moist and uniform.
Let the cake rest fully wrapped until it reaches room temperature. For the best texture, allow it to sit for several hours or even overnight. The crumb becomes smoother, more cohesive, and deeply flavorful with time.
To serve, trim off the browned edges with a serrated knife. Slice the cake evenly down the center, then cut each half into ½ to 1-inch slices. Each piece should hold its shape with a soft bounce and clean edges.
Recipe Tips
Whip the eggs long enough to hold a ribbon trail when lifted:
This stage builds the necessary volume for a tall, fluffy cake.
Always sift the flour for a smooth, lump-free texture:
Fine flour blends effortlessly and prevents overmixing.
Wrap the cake in plastic wrap while still warm to lock in moisture:
This technique preserves softness and enhances the cake’s signature texture.
Avoid overmixing to prevent deflating the foam:
Gentle folding keeps the batter light and airy.
Let the cake rest overnight for the best possible texture and flavor:
Time allows the crumb to mature into a perfect, moist sponge.
What to Serve With This Recipe
This elegant sponge pairs beautifully with tea. Matcha, jasmine, or roasted green teas balance the cake’s sweetness with earthy or floral notes. For a Western touch, serve it with strong black coffee or espresso.
Top slices with whipped cream and fresh berries for a refined dessert. Strawberries, raspberries, or even figs create a vivid contrast in both flavor and presentation.
You can also layer thin slices with custard, jam, or whipped mascarpone to create individual plated desserts. Their soft texture makes them easy to stack and dress up elegantly.
As a sweet companion to a traditional Japanese tea set, Castella offers just the right amount of sweetness to balance delicate brews like sencha or gyokuro.
Creative Variations
Brighten the flavor with yuzu zest or citrus extract. A little goes a long way in lifting the overall profile.
Swap part of the white sugar with light brown sugar for deeper caramel undertones. It gives the cake a toasty finish without overpowering the honey.
For a floral twist, infuse the honey mixture with lavender or rosewater. These subtle infusions complement the vanilla and enhance the cake’s aromatic charm.
To add visual appeal and flavor depth, swirl in matcha or cocoa powder before baking. The marbled effect turns each slice into a delicate work of art.
Frequently Asked Questions
Why didn’t my cake rise evenly?
Uneven mixing, temperature variations, or under-whipped eggs can cause lopsided rise. Always whip the eggs thoroughly and bake at a steady temperature.
Can I use all-purpose flour instead of cake flour?
While possible, all-purpose flour results in a denser texture. For the signature lightness of Castella, cake flour is best.
How long can I keep Castella cake?
Wrapped tightly, it stays fresh at room temperature for up to 3 days. For longer storage, refrigerate it for up to 5 days or freeze for up to a month.
Is it okay to skip wrapping it in plastic?
Wrapping is essential—it locks in moisture and gives the cake its silky, springy texture. Skipping this step can lead to a dry, uneven crumb.
With its signature bounce and delicate sweetness, Castella Cake is a beautiful example of refined simplicity. Every bite is soft yet structured, light yet satisfying. When made with care and a bit of patience, this timeless sponge rewards you with a moist, flavorful crumb that tastes even better the next day. Whether enjoyed with tea or transformed into an elegant plated dessert, Castella is a cake worth mastering.
Ingredients
1½ cups cake flour
6 large eggs, at room temperature
1 cup granulated sugar
¼ cup honey
2 tablespoons warm water
2 teaspoons vanilla extract
½ teaspoon salt
Instructions
Begin by preparing a stand mixer fitted with a whisk attachment. Crack the eggs into the mixing bowl and add the granulated sugar. Whip the mixture on high speed for 6 to 8 minutes until it becomes pale, voluminous, and mousse-like in texture. The batter should thicken and appear creamy, resembling a smooth custard base.
Meanwhile, preheat your oven to 315°F (157°C). Prepare an 8×8-inch metal baking pan by lightly coating it with nonstick spray. Line the base and all sides with parchment paper, ensuring the parchment extends at least an inch above the rim—this allows room for the cake to rise without spilling over.
In a separate small bowl, combine the honey, warm water, vanilla extract, and salt. Stir until the honey is fully dissolved and the mixture is smooth.
Reduce the mixer speed to low and slowly incorporate the honey mixture into the whipped eggs. With the mixer still on low, gradually sift and fold in the cake flour. Mix only until the flour disappears—avoid overbeating to preserve the batter’s lightness.
Carefully pour the finished batter into the prepared pan. Gently tap the pan once or twice on the counter to release any large air bubbles, being cautious not to deflate the airy batter.
Place the pan in the center rack of the preheated oven. Bake for approximately 45 minutes, or until the top turns a rich golden brown and develops a puffed, domed surface.
Once baked, lift the cake out of the pan using the edges of the parchment paper. While still warm, gently remove the parchment and wrap the cake tightly in plastic wrap. This step traps moisture inside, encouraging a soft, tender texture throughout the loaf.
Allow the cake to cool completely at room temperature while wrapped. For optimal texture, keep the cake wrapped for several hours or overnight—up to 24 hours enhances the delicate crumb.
To serve, use a serrated knife to trim the browned edges from each side. Slice the cake down the center to form two even loaves, then cut each loaf into uniform pieces between ½ to 1 inch thick. The result is a soft, golden sponge cake with an ultra-moist interior and a delicate, slightly chewy bite.
Castella Cake Recipe
Ingredients
- 1½ cups cake flour
- 6 large eggs at room temperature
- 1 cup granulated sugar
- ¼ cup honey
- 2 tablespoons warm water
- 2 teaspoons vanilla extract
- ½ teaspoon salt
Instructions
- Begin by preparing a stand mixer fitted with a whisk attachment. Crack the eggs into the mixing bowl and add the granulated sugar. Whip the mixture on high speed for 6 to 8 minutes until it becomes pale, voluminous, and mousse-like in texture. The batter should thicken and appear creamy, resembling a smooth custard base.
- Meanwhile, preheat your oven to 315°F (157°C). Prepare an 8×8-inch metal baking pan by lightly coating it with nonstick spray. Line the base and all sides with parchment paper, ensuring the parchment extends at least an inch above the rim—this allows room for the cake to rise without spilling over.
- In a separate small bowl, combine the honey, warm water, vanilla extract, and salt. Stir until the honey is fully dissolved and the mixture is smooth.
- Reduce the mixer speed to low and slowly incorporate the honey mixture into the whipped eggs. With the mixer still on low, gradually sift and fold in the cake flour. Mix only until the flour disappears—avoid overbeating to preserve the batter’s lightness.
- Carefully pour the finished batter into the prepared pan. Gently tap the pan once or twice on the counter to release any large air bubbles, being cautious not to deflate the airy batter.
- Place the pan in the center rack of the preheated oven. Bake for approximately 45 minutes, or until the top turns a rich golden brown and develops a puffed, domed surface.
- Once baked, lift the cake out of the pan using the edges of the parchment paper. While still warm, gently remove the parchment and wrap the cake tightly in plastic wrap. This step traps moisture inside, encouraging a soft, tender texture throughout the loaf.
- Allow the cake to cool completely at room temperature while wrapped. For optimal texture, keep the cake wrapped for several hours or overnight—up to 24 hours enhances the delicate crumb.
- To serve, use a serrated knife to trim the browned edges from each side. Slice the cake down the center to form two even loaves, then cut each loaf into uniform pieces between ½ to 1 inch thick. The result is a soft, golden sponge cake with an ultra-moist interior and a delicate, slightly chewy bite.
