Chocolate Castella Cake

Name: Chocolate Castella Cake (Light & Fluffy)
Prep time: 20 min
Cook time: 50 min
Total time: 1 h 20 min
Yield: 10 servings
Cuisine: American
Ingredients: 40 g all-purpose flour; 80 g granulated sugar; 20 g natural, unsweetened cocoa powder; 60 g milk; 60 g vegetable oil; 4 medium eggs (room temperature)

Chocolate castella cake is a light, pillowy sponge cake made with eggs, cocoa powder, and minimal flour that delivers rich chocolate flavor without heaviness. Its signature cotton-soft crumb makes it irresistible for chocolate lovers seeking a refined dessert.

🌍American 🏷️Chocolate castella cake

Total

1h 20m

Servings

10

Difficulty

Hard

Est. Cost

$14–$23

Recipe Source

View original recipe

From Thecakegirls · by Brenda Maher

Ingredients

40 g all-purpose flour

80 g granulated sugar

20 g natural, unsweetened cocoa powder

60 g milk

60 g vegetable oil

4 medium eggs (room temperature)

6 Ingredients

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Instructions

1
Separate 4 large eggs into yolks and whites in two bowls. Warm 60g vegetable oil in the microwave for 40 seconds and set aside.
2
Sift 40g all-purpose flour and 20g unsweetened cocoa powder into the bowl of oil. This ensures a smooth, lump-free batter.
3
Add 60g sugar-free milk (room temperature) and 4 egg yolks to the dry mixture. Whisk until smooth and velvety.
4
Gradually add 70g granulated sugar to the egg whites and beat until soft peaks form. The whites should hold their shape without collapsing.
5
Add a small scoop of egg whites to the cocoa mixture to lighten it. Gently fold the rest of the egg whites into the batter without deflating it.
6
Line a 15 x 15 x 7 cm square mold with parchment paper and wrap it in foil. Place the mold in a water bath with 80°C hot water filling halfway up the sides.
7
Pour the batter into the mold and bake at 150°C for 50 minutes. The water bath ensures an even bake and prevents cracking.
8
Remove the cake from the mold and peel off the parchment paper. Let it cool completely on a wire rack before slicing and enjoying.

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Tips & Notes

Pro tips

Separate eggs carefully—even a trace of yolk in whites prevents proper whipping. Whip egg whites to stiff peaks for maximum lift and airy crumb.
Sift cocoa powder and flour together to eliminate lumps and incorporate air, preventing dense pockets in the final cake.
Fold the chocolate batter into whipped egg whites in two additions using a rubber spatula with an under-and-over motion to preserve volume.
Do not open the oven door during baking. Check doneness only in the last 5 minutes to prevent collapse from temperature shock.

Substitutions

All-purpose flour → cake flour (reduce to 35 g for extra tenderness)
Vegetable oil → melted butter (note: use equal weight; butter adds richer flavor but slightly less lift)
Natural cocoa powder → Dutch-process cocoa (use same amount; flavor will be deeper and less acidic)

Storage & make-ahead

Store in an airtight container at room temperature for up to 3 days, or refrigerate for 5 days. Reheat gently in a 300°F oven for 10 minutes to restore softness.

Common Questions

Why is my castella cake dense instead of fluffy?

Overmixing the batter deflates air from whipped eggs. Fold ingredients gently until just combined, and ensure eggs are room temperature for maximum volume.

Can I make chocolate castella cake without a loaf pan?

Yes, use an 8-inch square cake pan or round pan. Adjust baking time by 5–10 minutes; check doneness with a toothpick.

How do I know when the castella is done baking?

A toothpick inserted in the center should come out clean or with a few moist crumbs. The cake should spring back when gently pressed.

Can I substitute cocoa powder with melted chocolate?

Yes, replace 20 g cocoa powder with 30 g melted dark chocolate. Reduce vegetable oil by 10 g to maintain texture balance.

How should I store leftover castella cake?

Keep in an airtight container at room temperature for up to 3 days, or refrigerate for up to 5 days. Reheat briefly in a low oven to restore softness.