Chocolate Castella Cake

This Japanese-style castella cake gets its signature airy, sponge-like texture from whipped egg whites folded gently into a rich chocolate batter, then baked slowly in a water bath. The water bath keeps the oven's heat gentle and even, which is key to the cake's soft, jiggly crumb. It takes a bit of technique with the egg whites, but the payoff is a light, delicately sweet dessert unlike a typical chocolate cake.

Whipped egg whites are folded into a chocolate batter and baked in a water bath for a light, sponge-like Japanese cake.

Why You'll Love This Recipe

• Fast: ready in about 90 minutes (25 min prep, ? min cook)
• Simple: 9 everyday ingredients
• Feeds the family: 8 servings

Ingredients

• 100 g cake flour
• 95 g vegetable oil
• 18 g cocoa powder
• 25 g dark chocolate
• 100 g milk
• 8 eggs
• 95 g granulated sugar
• 8 g vanilla extract
• 8 g lemon juice

Instructions

1. Heat the oven to 320°F (160°C), separate the eggs, keep the egg whites chilled in the fridge, and heat the vegetable oil to 158°F (70°C).
2. Transfer the heated oil to a clean bowl, add the cocoa powder and flour, and mix well, then stir in the melted dark chocolate and milk, followed by the egg yolks, and set the mixture aside.
3. Add the lemon juice, granulated sugar, and vanilla extract to the egg whites, then beat with a hand mixer until soft peaks form.
4. Fold a scoop of the whipped egg whites into the batter first to loosen it, then pour in the rest and gently fold until just combined.
5. Line a square springform pan with parchment paper, pour in the batter, smooth the surface, and tap the pan gently a few times if you like.
6. Wrap the bottom of the pan in foil to keep water out, pour about an inch of room-temperature water into a larger baking sheet, place the springform pan inside, and bake for 65 minutes.
7. Once fully baked, remove the cake from the oven, take it out of the springform pan, and let it cool on a wire rack so it doesn't turn overly moist.

Cooking Tips

• Chill the egg white bowl before whipping to help it reach stiff peaks more easily.
• Fold the egg whites into the batter gently, in stages, to keep as much air in as possible.
• Wrap the pan bottom tightly in foil so no water leaks into the batter during baking.

Substitutions

• Milk chocolate can replace dark chocolate for a sweeter flavor.
• A round cake pan can be used if you don't have a square springform pan, adjusting the bake time slightly.
• Lime juice can be used in place of lemon juice in the egg whites.

Storage

• Store in an airtight container in the refrigerator for up to 3 days.
• Bring to room temperature before serving for the best texture.

Serving Suggestions

• Slice with a warm, clean knife for the neatest pieces.
• Serve plain or with a light dusting of cocoa powder.
• Pair with fresh berries or a cup of tea.

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