Decadent Chocolate Cake Roll

IMPORTANT: For accuracy, I would recommend using the gram measurements provided, as those are the exact quantities I use. Cup measurements are given as estimates (based on US cup measurements) to make it easier for those who do not have a scale.

Ingredients

Dark Chocolate Ganache

▢ 1½ cups (250 g) semi-sweet or dark chocolate - I use 50% dark chocolate
▢ 1 cup (240 g) whipping cream or heavy cream

Whipped Cream

▢ 1¾ cups (400 g) cold whipping cream or heavy cream
▢ 2 tbsp (17 g) powdered sugar - also known as icing or confectioners sugar
▢ ½ tsp vanilla essence/extract

Instructions

Chocolate Sponge Cake

Preheat oven to 170 °C (340°F) with the fan on/convection mode (see note 1 if you don't have a fan function) and line an 18x13 inch (half-sheet) baking tray. Only line the tray longways, leaving the two long edges of the pan exposed (see video for demonstration).
In a bowl combine the flour, cornstarch, cocoa powder, baking powder and salt. Using a whisk or fork, mix until well combined (there's no need to sift it just yet). Set aside for now.
In a small bowl combine milk, oil and instant coffee powder. Give it a mix and then set aside for now as well.
Next separate the yolks and whites from your eggs. Ensure no egg yolks get into the egg whites. Set aside.
In a large bowl add in 1 tbsp of warm water, and a ⅓ cup (66g) of white sugar (the portion of sugar assigned for the egg yolks) and mix so that the sugar is coated in the water. Next add in the 6 egg yolks and vanilla, and using a hand or stand mixer on a medium speed, whip until the mixture is thick and pale. You should be able to create ribbons with it that settle on the top of the mixture for a few seconds before being absorbed back in. This should roughly take 5 minutes but will vary depending on your mixer. Once done set aside for now.
In another large bowl add in the 6 egg whites. Using a hand or stand mixer (with clean attachments - see note 2), whip for 30 seconds until it's frothy, and then gradually add in ⅔ cups (133g) of white sugar while continuously mixing. Once the sugar is mixed in, continue to whip until you reach soft peaks. This should take about 7 minutes, but will vary depending on your mixer. We don't want stiff peaks so keep checking the egg whites to check they aren't being overwhipped (see video demonstration).
Add half of the whipped egg whites into your egg yolk mixture and using a spatula, gently fold until it's just combined. Fold gently as we want to try and retain as much air in the batter as possible. Next sift the dry ingredients into the bowl and fold until just combined. Once done, add in the remaining egg whites and fold until just combined.
To finish off, add in the milk/oil/coffee mixture and fold until just combined. Your mixture should be thick and flowy once done (see video demonstration). If the batter is too thick, it just means you need to fold the batter a little more.
Distribute the batter evenly into the lined baking tray and using an offset spatula (or anything that has a straight edge), even out the batter as much as possible. Once done, shake the tray to even out the batter further, and then drop the tray on the counter a few times to remove any large air bubbles. I also like to tap the bottom of the tray with my hands a few times.
Bake for 18 minutes, or until the top is set. You know it's ready when you touch the top of the sponge gently with your finger, and it makes an indent which slowly springs back. Allow to cool in the tray for 15 minutes.
While it's cooling, prepare some parchment paper that we are going to be using to roll the cake roll. If your parchment paper isn't large enough, then overlap two sheets. Lightly grease the parchment paper with unflavoured vegetable oil, by dabbing your fingers into the oil and then spreading it onto the parchment paper. We only want a very thin layer (see note 3).
After 15 minutes, run a knife along the edges of the sponge that are stuck to the baking tray to help release the sponge, and then turn the sponge out onto the parchment paper.
Roll the sponge up using the parchment paper while its still slightly warm. Set aside to cool (we will unroll it again later).

Dark Chocolate Ganache

While the cake roll is cooling, prepare the ganache. In a microwave safe bowl combine chocolate and cream. Heat in the microwave (or you can use a double boiler) until the cream becomes hot and the chocolate begins to melt. Be sure not to overheat the cream. Mix until the chocolate is completely melted and the mixture is smooth. Set aside to cool and thicken - I like to pop my ganache into the fridge to speed up the process.

Whipped Cream

10 minutes before assembling the cake roll, whip the cream.
In a large bowl add in the cream, powdered sugar and vanilla. Whip on a medium speed until you reach stiff peaks. Be careful not to overwhip the cream, so keep a close eye on it once it starts to thicken up.

Assembly

Once the cake roll is cool, unroll it gently. Using a serrated knife, trim off the short edges at an angle (see video demonstration).
Spread half of the cooled ganache evenly over the top of the cake roll. We will save the other half for later.
Next spread a layer of the cream on the sponge, leaving a small gap at the end (see note 4).
To roll, lift up the edge of the sponge (that is opposite to the end that has the small gap) with the parchment paper, and push the top edge of the sponge into the cream to create an initial tight roll, and then using the parchment paper, continue to roll the sponge until you reach the end. You want to push gently while rolling so you have a tight roll, but don't push too hard otherwise you may push too much of the cream out.
Once you get to the end, use the parchment paper to help lift the cake roll and place it onto a wire rack with a tray underneath. Carefully remove the parchment paper.
Pour the remaining ganache over the top of the cake roll, using an offset spatula or knife to help spread out the ganache. If the ganache is too thick (this usually happens if it has been setting for too long), simply heat it up a little until it becomes a more spreadable consistency.
Allow the cake roll to set in the fridge for 1 hour before transferring to a serving platter (see note 5). Slice a small piece off of each edge to reveal a wonderful clean chocolate cake roll. Enjoy!

Notes

Note 1. In this recipe I use an oven with the fan function turned on. The fan forced function cooks food faster, so if your oven doesn't have a fan option, then you will need to increase the baking temperature to 185°C (365°F) so that the sponge cake bakes at the same rate as mine 🙂

Note 2. There should be no fat residue on the attachments of your mixer or in the bowl you mix the egg whites in as any fat will prevent the meringue from whipping up properly.

Note 3. Greasing the parchment paper is so that the crust of the cake roll doesn't stick to it when we come to rolling the sponge. By using your fingers to grease the parchment paper, it helps with achieving only a very thin layer of oil, which is harder to achieve when using a pastry brush.

Note 4. Leaving a small gap at the end of the cake roll will ensure that the cream doesn't seep out the cake roll when you're rolling it.

Note 5. I like to use two offset spatulas to help me move the cake roll onto a serving platter. Two knives should do the trick too. Simply slide the spatulas or knives under the cake roll, and lift it off the rack and place onto your serving plate. See video for visual demonstration.

Nutritional information are estimates only as they are automatically calculated by a third party application. Actual values may differ based on brands and types of products used.