You can't imagine how delicious a simple cake roll can be!

A subtle hint of coffee and a hint of chocolate blend together for a truly extraordinary treat.

◆ Coffee Cocoa Cake Roll

• Coffee-Flavored Chiffon Cake Batter

4 medium-sized eggs (50g each, shelled), 68g cake flour, 65g granulated sugar, 50g corn oil, 55g espresso, 1g salt

• Cocoa Butter Filling

200g heavy cream, 18g granulated sugar, 12g cocoa powder

• Instructions

First, make two espressos.

I used a home espresso machine. After grinding the coffee beans, I made two espressos (30ml each). This yielded approximately 60ml of espresso. After cooling, take out 55g of the mixture. If you don't have an espresso machine, dissolve 4 grams of pure instant coffee powder (must be pure instant coffee, without sugar or creamer) in 50 grams of hot water. Let the resulting mixture cool before use.

Separate the egg yolks and egg whites. In a large bowl, add the egg yolks and salt, corn oil, and espresso. Whisk until combined.

Sieve the cake flour into the liquid and mix thoroughly with a spatula to form a batter.

In another bowl, whisk the egg whites. Add the granulated sugar to the egg whites in 2-3 portions and beat on high speed with an electric whisk. Whisk until soft peaks form when the whisk tip is gently lifted. The beaten egg whites should be very fine; do not overbeat.

Add 1/3 of the beaten egg whites to the batter and mix thoroughly with a spatula. Add another 1/3 of the egg whites and continue mixing.

Then, pour the batter back into the egg white bowl and mix again until a smooth, creamy cake batter forms.

The batter should be very thick and creamy. Stir frequently during mixing to combine quickly and thoroughly. Avoid mixing for too long, which can cause the egg whites to deflate. If the batter becomes watery or lumpy, this indicates deflated egg whites, and the cake will not bake smoothly.

Pour the cake batter into a baking pan lined with baking paper (this recipe is for a 28cm square pan), smooth the batter, and shake the pan a few times on the countertop. Prepare to bake.

Preheat the oven to 180°C/350°F (preheating can be done while beating the egg whites). Place the pan in the preheated oven on the middle rack. Bake at 180°C/350°F for approximately 15 minutes. Please adjust the baking temperature and time according to your oven's specifications. Remember to use a humidity control insert in a steam oven (for ovens with excellent sealing, such as steam ovens and built-in ovens, a humidity control insert or cardboard should be added to keep the oven door slightly open for a successful chiffon cake. This is not necessary in a regular oven).

After taking the cake out of the oven, lift the cake roll out of the baking pan by the parchment paper.

Immediately flip it over onto a new sheet of parchment paper, bottom side up, and peel off the bottom sheet. Then, loosely cover the cake with the parchment paper and let it cool.

After the cake has cooled, place a new sheet of parchment paper on the countertop and flip the cake over onto the new sheet (bottom side up). It doesn't matter if the top crust of the cake roll gets stuck (it will roll inwards).

Trimming the edges of the cake. Select two edges and use a serrated knife to cut off a diagonal strip (trimming is for a better cut of the cake roll, but it's also fine if you don't trim it).

• Make the cocoa buttercream.

Add sugar and cocoa powder to the heavy cream and whip until the peaks are stiff. (Which whipping method requires cold water. If the room temperature is warm, do this in a well-air-conditioned room.)

If you prefer a stronger cocoa flavor, increase the cocoa powder to 18 grams.

Spread the cocoa cream onto the cake slices. Roll up the cake from the trimmed edge. Once you reach the end, wrap the cake roll in baking paper. Refrigerate the cake for 2 hours before cutting. (Sufficient refrigeration will help the cake roll retain its shape, solidify the cream filling, and make it look prettier when cut.)

Chill thoroughly and slice, then enjoy!