Choco Castella Cake

• •150 ml Whole Milk
• •90 ml Neutral Vegetable Oil (such as canola or sunflower oil)
• •105 g Cake Flour (sifted)
• •30 g Unsweetened Cocoa Powder (sifted)
• •9 piece Large Egg Yolks
• •9 piece Large Egg Whites
• •0.5 tsp Cream of Tartar (or 1 tsp lemon juice)
• •120 Granulated Sugar
• •0.3 cup Chocolate Chips (optional, for topping)

Instructions

1. 1

   Preheat your oven to 150°C (300°F). Prepare a 24x24cm (9.5x9.5 inch) high-sided square baking pan by lining the bottom and sides with parchment paper, extending above the rim. Also, prepare a larger baking pan or roasting pan for the water bath (au bain marie technique).

2. 2

   In a microwave-safe bowl, heat the vegetable oil for about 1 minute until warm to the touch (40-50°C / 105-120°F). In a separate large bowl, combine the sifted cake flour and cocoa powder. Add the warm oil and milk to the dry ingredients, mixing with a whisk until smooth and well combined.

3. 3

   Whisk in the egg yolks into the chocolate-milk mixture until thoroughly incorporated and smooth. Set this batter aside.

4. 4

   In a very clean, large bowl, using an electric mixer, beat the egg whites and cream of tartar (or lemon juice) on medium speed until foamy. Gradually add the granulated sugar, a tablespoon at a time, while continuing to beat on medium-high speed. Continue mixing until you reach medium peak stiffness – the whites should hold a soft peak that curls slightly at the tip when you lift the whisk.

5. 5

   Gently fold about one-third of the whipped egg whites into the chocolate-egg yolk batter using a whisk, mixing until just combined. This lightens the batter, making it easier to incorporate the rest of the whites.

6. 6

   Carefully add the remaining egg whites to the lightened chocolate batter. Using a spatula, gently fold the mixture together with an 'over and under' motion, being careful not to deflate the egg whites, until the batter is homogeneous and no streaks of egg white remain.

7. 7

   Pour the batter into the prepared baking pan. Tap the pan gently on the counter a few times to release any large air bubbles. If using, sprinkle chocolate chips evenly over the surface.

8. 8

   Place the baking pan inside the larger water bath pan. Pour hot water into the larger pan until it reaches about halfway up the sides of the cake pan. Carefully transfer to the preheated oven and bake for 60-90 minutes, or until a wooden skewer inserted into the center comes out clean. The cake should be golden brown and spring back when lightly touched. (The original recipe specified 80 minutes for their oven).

9. 9

   Once baked, carefully remove the cake pan from the water bath and let it cool completely in the pan on a wire rack. Once at room temperature, gently unmold, slice, and serve.

Chef's Tips

• 💡Do not overmix the batter at any stage, especially when folding in the egg whites. Overmixing can lead to a dense cake.
• 💡Ensure your egg whites bowl and whisk are absolutely grease-free for best whipping results.
• 💡The water bath is crucial for a moist, tender crumb and to prevent cracking. Make sure the water level is consistent throughout baking.
• 💡Allow the cake to cool completely before slicing for the best texture and to prevent it from tearing.