📝 About This Recipe
Brought to Japan by Portuguese merchants in the 16th century, Castella (Kasutera) has evolved into a quintessential Japanese Wagashi known for its incredibly fine, bouncy crumb and signature dark brown crust. Unlike Western sponge cakes, it uses no oil or butter, relying instead on the alchemy of bread flour and intensive whisking to create a chewy, 'mochi-mochi' texture. Infused with floral honey and aged overnight to develop moisture, this cake is a masterclass in elegant simplicity.
🥗 Ingredients
The Batter Base
- 6 pieces Large Eggs (must be at room temperature)
- 200 grams Bread Flour (sifted twice; bread flour is essential for the chewy texture)
- 200 grams Granulated Sugar (caster sugar works best for easy dissolving)
The Sweetening Infusion
- 4 tablespoons Honey (mild floral honey like acacia or clover)
- 2 tablespoons Warm Water (approximately 110°F to dissolve the honey)
- 1 tablespoon Mirin (adds a subtle sheen and depth of flavor)
Traditional Finishing
- 2 tablespoons Zarame Sugar (large crystal coarse sugar for the bottom crunch)
👨🍳 Instructions
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1
Preheat your oven to 320°F (160°C). Line a 7x7 inch (or 8x5 inch loaf pan) with high-quality parchment paper, ensuring the paper stands at least 2 inches above the rim of the pan to allow for rising.
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2
In a small bowl, whisk together the honey, warm water, and mirin until the honey is completely dissolved and the mixture is fluid. Set aside.
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3
Place the 6 room-temperature eggs in a large, clean glass or metal bowl. Using a stand mixer or hand mixer, begin beating on medium speed until the eggs are broken up and slightly foamy.
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4
Add the granulated sugar in three separate additions, increasing the mixer speed to high. Beat for approximately 8-10 minutes. The mixture should become pale yellow, thick, and reach the 'ribbon stage'—where the batter falling from the whisk holds its shape for several seconds.
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5
Lower the mixer speed to medium-low and slowly pour in the honey-mirin mixture. Mix for another 1 minute to ensure even distribution.
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6
Add the sifted bread flour in three batches. Use the mixer on its lowest speed for only 15 seconds per batch, then finish folding by hand with a spatula to avoid over-deflating the eggs while ensuring no flour pockets remain.
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7
Sprinkle the Zarame (coarse) sugar evenly over the bottom of the lined cake pan. This creates the iconic crunchy bottom characteristic of high-end Nagasaki Castella.
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8
Pour the batter into the pan from about 12 inches above; this height helps break large air bubbles as the batter falls. Drag a skewer or toothpick through the batter in a zig-zag motion to pop any remaining large bubbles.
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9
Tap the pan firmly on the counter twice. Bake at 320°F (160°C) for 45-50 minutes, or until the top is a deep, dark mahogany brown and a skewer comes out clean.
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10
Immediately upon removing from the oven, drop the pan from a height of 5 inches to prevent the cake from shrinking too much as it cools.
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11
This is the secret step: while the cake is still hot, wrap it tightly (including the parchment paper) in plastic wrap. This traps the steam, which migrates to the surface to create the moist, tacky texture the cake is famous for.
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12
Store the wrapped cake in the refrigerator for at least 24 hours (up to 48 hours is better). This 'aging' process allows the flavors to mature and the moisture to even out.
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13
To serve, trim off the side crusts with a very sharp serrated knife to reveal the perfect yellow crumb. Slice into thick rectangular blocks.
💡 Chef's Tips
Use bread flour instead of cake flour; the higher protein content is what gives Castella its unique bouncy and chewy 'Koshi' texture. Never skip the aging process—eating it fresh will result in a dry, uninspiring sponge; 24 hours in plastic wrap transforms it completely. Ensure your eggs are truly at room temperature; cold eggs will not achieve the volume necessary for a light rise without chemical leaveners. If the top is browning too quickly, loosely tent a piece of foil over the pan after 30 minutes of baking. Clean your knife with a damp warm cloth between every slice to ensure the edges of the cake look professional and sharp.
🍽️ Serving Suggestions
Serve with a bowl of hot, frothy Matcha green tea to balance the sweetness of the honey. A side of lightly sweetened whipped cream and fresh strawberries makes for a lovely modern fusion dessert. Pair with a glass of cold milk—the way many Japanese children traditionally enjoy this treat. Enjoy as a sophisticated afternoon snack with a cup of roasted Hojicha tea. If the cake is a few days old, lightly toast a slice and top with a tiny pat of salted butter.