Chocolate Sponge Cake

With its moist and airy texture, this cloud-like chocolate sponge cake is a true treat for chocolate lovers.

This recipe guides you through each step, from lining the baking pan with parchment paper to achieving the perfect consistency of the batter. The cake bakes to perfection in a water bath, ensuring a tender and even crumb.

Whether served hot right out of the oven or chilled after being stored, this chocolate sponge cake is a versatile and decadent dessert. Feel free to add your personal touch with a dollop of whipped cream or any frosting that suits your taste.

Now get ready to savor each delightful bite of this chocolate flavored cloud~

Hot Oil Method for making a perfect chocolate sponge cake

As I have introduced in my classic chiffon cake recipe, there are three methods for making chiffon cake: All Together Method, Flour Oil Method, and Hot Oil Method.

• The All Together Method involves mixing all the ingredients together, but this can lead to the formation of too much gluten, resulting in a dense cake.
• The Flour Oil Method combines the flour and oil first, creating a protective layer around the flour particles to prevent gluten formation. This method increases the success rate and produces fluffy cakes.
• The Hot Oil Method, a variation of the Flour Oil Method, involves heating the oil to 70-80°C before mixing it with the flour to further prevent gluten formation. When the oil is hot, it can be more thoroughly combined with flour, leading to a smoother batter and a more even distribution of fats in the cake. This, in turn, helps to create a lighter and more delicate texture.

In this chocolate sponge cake recipe, I am going to use hot oil method to achieve a supremely smooth and airy texture.

However, caution is needed if you use the hot oil method, because if you accidentally make the oil overly hot, it will burn all the proteins and cause the chiffon cake to fail to rise.

If you do not have a food thermometer, you can simply skip the oil heating process and instead use the flour oil method. This alternative method will still yield a fluffy and airy chocolate sponge cake.

How to beat egg whites for chocolate sponge cake?

Many “foolproof” chocolate sponge cake recipes would suggest you to beat the egg white until stiff peaks form. Yes, it’s the easiest way for a novice baker to get started with.

When you achieve stiff peaks with the egg whites in your sponge cake, you can still expect a tall, fluffy, and delicious result. However, it is worth noting that this may also lead to several cracks on the top surface of the cake. Additionally, the distribution and size of the bubbles within the cake might be inconsistent.

However, if the egg whites are not whipped up enough, let’s say you stopped whipping at the soft-peak stage, there isn’t enough air trapped in the egg whites, your sponge cake won’t rise tall enough to be airy and fluffy.

Therefore, I always whip my egg whites until medium peaks form, which is between stiff peaks and soft peaks stage.

Soft vs Medium vs Stiff peaks of egg whites

When using my hand mixer with 5 speed levels, I usually use speed 3 to whip the egg whites. With this setting, it typically takes approximately 8 minutes to achieve medium peaks when beating 3 egg whites. And it usually requires around 15 minutes of whipping to reach the desired medium peak consistency when beating 8 egg whites.

The time required may vary depending on the hand mixer and the quantity of egg whites being used. But it’s easy to observe the peaks to tell the stage of your egg whites:

• Soft peaks: when you hold your beaters up with the egg white peaks pointing to the ceiling, the soft peaks can barely hold its shape, and will blend down and point to the floor.

• Medium peaks: when you hold your beaters up with the egg white peaks pointing to the ceiling, the medium peaks will slowly bend down and eventually hold its shape at 45 degrees pointing to the floor.

• Stiff peaks: when you hold your beaters up with the egg white peaks pointing to the ceiling, the stiff peaks will hold its shape and point straight up to the ceiling.

How to line a rectangle baking pan with parchment paper

Step 1: Take a rectangular piece of parchment paper that is larger than the size of your baking pan. Place the baking pan on top of the parchment paper and draw along the four corners with a pencil or pen (ideally use an edible marker).

Step 2: Remove the baking pan from the parchment paper, and using a pair of scissors, cut along the marked dotted line as shown in the picture below.

Step 3: Create folds in the parchment paper as demonstrated in the picture below. Then, place the parchment paper back into the pan, ensuring that the folds align neatly with the edges of the pan. Secure the parchment paper in place with 4 toothpicks.

Last words before you start:

I used to prefer using egg shells to separate eggs. However, I discovered that the sharp edges of the egg shells often caused the egg yolk to break. As a result, I now prefer to separate eggs using my hands

As we all know, one single drop of egg yolk or oil could stop the egg white from being beaten stiff.

Therefore, no matter how great your egg separating skills are, I still highly recommend using three bowls (two small bowls, one large mixing bowl) to separate egg yolks and whites.

• Crack an egg into a small bowl
• Scoop up the egg yolk with your hands, with your fingers slightly spread apart, allowing the egg whites to slip through your fingers while keeping the yolk intact.
• Carefully transfer the yolk back and forth between your hands, allowing the remaining egg whites to fall into the bowl below. Be gentle to avoid breaking the yolk.
• Once all the egg whites have been separated, transfer the egg yolk to another small bowl.
• Pour the separated egg whites from the small bowl to a large mixing bowl. Repeat with the remaining eggs.

In this way, even if we accidentally break a yolk in the middle of the separating process, we will only “pollute” one egg white, and the other egg whites in the large mixing bowls are still clean and safe.

You can save the egg yolk polluted egg whites for scrambled eggs. But NEVER try to scoop out the egg yolk and keep using the polluted egg white.

EQUIPMENT for making chocolate sponge cake

• Kitchen scale or measuring cups (I will provide ingredient measurements in both grams and measuring cups. But I highly recommend using a kitchen scale for greater accuracy and to ensure a more successful final dish.)
• Baking pan (I used a 9x11x3 inch rectangle baking pan. You can also use two 8 inch round cake pans. Or Cut this recipe in half and use one 8 inch round cake pan.)
• Food thermometer
• Hand mixer
• Mixing bowls
• Parchment paper
• Oven

INGREDIENTS List 

• 8 extra large eggs (The weight of each extra large egg, including the shell, is approximately 63g. If you’re using large eggs instead, which weigh about 56g with the shell, you will need 9 eggs.)
• 100 g vegetable oil (⅓ cup + 2 tbsps; Or corn oil)
• 90 g cake flour (½ cup + 2 tbsps; Or use 72g all purpose flour + 18g cornstarch instead.)
• 40 g cocoa powder (4 tbsps)
• 120 g milk (½ cup; Or soymilk, coconut milk, oat milk, almond milk … )
• 1 tsp vanilla extract (optional)
• 15 g lemon juice (1 tbsp; You can get about 1 tbsp of lemon juice by squeezing half lemon.)
• 120 g granulated sugar (½ cup + 2 tbsp)

Step-by-step INSTRUCTIONS 

1. Line a baking pan with parchment paper (refer to the step-by-step image illustrations above). Preheat the oven to 295℉/145℃.

2. Separate 8 extra large eggs into yolks and whites. Place the egg yolks in a small bowl, set aside on countertop. Place the egg whites in a large mixing bowl, keep in the freezer.

3. Add 90g cake flour to a large mixing bowl. Use a small saucepan to heat up 100g vegetable/corn oil over medium heat until it reaches 165℉/75℃. Carefully pour the hot oil into the mixing bowl. Stir the mixture using a whisk until the cake flour is thoroughly incorporated with the oil.

4. Add 40g cocoa powder to the flour oil mixture, mix with a whisk until smooth. Then add 120g milk, 8 egg yolks, and 1 tsp of vanilla extract (optional) to the mixture, stir with a whisk until smooth. Set aside.

5. Take the egg white’s mixing bowl out from the freezer. You might observe that the edges of the egg whites have started to freeze. Add 1 tbsp of lemon juice and 40g sugar into the egg whites. Use medium speed (speed 3 out of 5) of a hand mixer to whip the egg whites for 3 minutes until fish eye size bubbles form.

6. Add another 40g sugar into the egg whites, use medium speed to whip the egg whites for 3 more minutes until the bubbles are too tiny to be seen.

7. Add the remaining 40g sugar into the egg whites, use medium speed to whip the egg whites until medium peak forms (*see the pictures in content above for the differences between “soft peaks” and “medium peaks”.) It will take approximately 15 minutes of total whipping time.

8. Scoop ⅓ of the egg whites into the egg yolk mixture, fold until well combined.

9. Transfer the egg yolk mixture to the egg white bowl, gently fold until the color looks even.

10. Pour the batter into the cake pan, gently spread the batter with a spatula to create a smooth surface. Drop the cake pan on the kitchen counter a couple of times to eliminate large bubbles from the batter.

11. Place the filled cake pan inside a larger cake pan or baking dish. Carefully pour cold water into the larger pan, taking care not to splash water into the cake batter. Add enough water to reach about halfway up the sides of the cake pan.

12. Gently transfer the pans to the preheated oven. Bake at 295℉/145℃ for 75 minutes.

13. Remove the cake pan from the oven, lift the cake pan out of the water bath, hold the edge of the parchment paper to lift the cake out of the cake pan. Place the cake on a wire rack, use a serrated knife to cut the cake into 8 pieces.

14. Serve the chocolate sponge cake hot immediately. Or allow the cake to cool completely, place it in an airtight container, and keep it in the fridge (for 3 to 4 days) or in the freezer (for 2 to 3 months). Feel free to decorate the cake with whipped cream (see my whipped cream recipe here) or any other frosting of your choice before enjoying it.

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