Place the chocolate and 2 tablespoons of cold water into a small bowl. Microwave on 50% power for 20-second intervals until the water is heated and the chocolate begins to melt. Stir the mixture until fully melted and thickened. Alternatively, melt the chocolate and water in a small saucepan over low heat, stirring continuously. Set aside to cool.

Once the chocolate mixture has cooled slightly, gently fold it into the egg yolk mixture.

With clean, dry beaters, beat the egg whites until soft peaks form. Be careful not to over beat.

Gently fold the egg whites into the chocolate mixture using a spatula, ensuring everything is evenly combined.

Pour the batter into the prepared tin, spreading it evenly. Bake in a preheated oven at 180°C (350°F) conventional, no fan, for about 17 minutes, or until just set.

Once the cake is baked, cover it with two layers of damp (wrung out) paper towels and one layer of dry paper towel. Refrigerate for 20 minutes.

While the cake cools, whip the cream until thick. Add icing sugar and vanilla essence and whip for a few more seconds until combined.

After 20 minutes, carefully peel off the paper towels from the cake. Dust the top of the cake with 1 tablespoon of sifted cocoa powder.

On another sheet of baking paper, sift more cocoa powder. Tip the cake onto the prepared sheet of paper, then gently peel off the lining paper.

Spread the whipped cream evenly over the cake. Using the baking paper to help, carefully roll the cake. Don’t worry if it cracks—this is normal and will come together once chilled. Twist the ends of the baking paper, cover the cake with plastic wrap, and refrigerate for 1–2 hours or overnight.

When ready to serve, unwrap the cake, place it on a serving plate, and dust with more cocoa powder. Slice and enjoy!

The cake will keep in the fridge for up to 5 days.