Chocolate Swiss Roll

4 eggs, separated
83ml + 125ml granulated sugar
5ml vanilla
125ml flour
45ml cocoa powder plus extra for dusting before rolling
5ml baking powder
1,2ml salt
62ml butter
15ml espresso powder

Cream filling:
250ml whipping cream
45ml icing sugar
5ml vanilla

For the topping:
160g chocolate, chopped
125ml cream
5ml corn syrup

Preheat your oven to 180℃. Spray and line the bottom (not the sides) of a 38cm X 25cm X 2,5cm baking tray with baking paper. Spray the paper lightly with a cooking spray.
Add the egg whites to the bowl of a stand mixer fitted with the whisk attachment.
Turn the mixer to high speed, add the 83ml sugar and whisk for 5 minutes until the mixture is stiff. Set aside.
Add the egg yolks, 125ml sugar and vanilla to a mixing bowl and beat for 2 minutes with electric beaters.
Sift the flour, cocoa powder, baking powder and salt into another mixing bowl.
Add the espresso powder to the dry ingredients.
Melt the butter and pour it over the dry ingredients.
Add the egg yolk mixture as well and beat on medium speed until the ingredients are combined.
Now fold in the stiff egg whites by stirring in a third and then gently folding in the rest. Keep folding until there are no white streaks in the batter.
Spoon the batter into the prepared baking tray and spread it evenly into a thin layer.
Bake for 10 minutes.

Rolling the cake:
Place a thin kitchen towel on a work surface and sift about 30ml cocoa powder over the towel.
Take the cake directly from the oven, run a sharp knife around the edges of the pan and immediately invert the cake onto the cocoa powder/kitchen towel.
Gently peel off the baking paper and roll the cake and the kitchen towel in a coil.
Set aside to cool completely.

Making the cream filling:
Pour the whipping cream into a mixing bowl, sift over the icing sugar and add the vanilla.
Beat the mixture with electric beaters until it is stiff enough to have a spreadable consistency.
Unroll the cold cake and remove it from the kitchen towel.
Spread the cream filling over the surface and roll the cake once again.
Place the Swiss roll on a cooling rack to cover with the chocolate topping.

For the chocolate topping:
Add all the ingredients to a heatproof bowl and set it over a saucepan with barely simmering water.
Stir until the chocolate has melted completely and the mixture is amalgamated.
Take the bowl from the heat and set aside for about 15minutes, stirring it every now and then so that it cools down a bit.
Pour the chocolate over the Swiss roll and spread it slightly with a spatula. Wait for the first batch/layer to set slightly before pouring the rest of the chocolate over the cake.
Allow the cake to stand on the cooling rack until the topping has set completely.

Transfer the Swiss roll to a serving plate and enjoy!