Combine the mascarpone cheese, mashed bananas, banana flavoring, and sugar. Mix all the ingredients together. Refrigerate.

Preheat the oven to 200°C/400°F. Place a rack in the center of the oven.

Using an electric mixer, beat the egg whites on high speed for 20 seconds. While beating, gradually add the sugar until soft peaks form.

Add the egg yolks, vanilla and flour. Stir gently with a spatula incorporating the batter.

Spread immediately over a 35x27cm/14×11 inches cookie pan lined with parchment paper.

Bake for 10-12 minutes or until you insert a toothpick in the center of the cake and it comes out clean.

Invert the cake onto a smooth kitchen towel.

Remove the top piece of the parchment paper.

Tightly roll up the cake with the towel starting with its shorter end. Allow to cool down completely on a wire rack.

Unroll the cake on a counter top, remove the towel and spread the Nutella evenly.

Spread the chilled mascarpone – banana filling evenly on top of the Nutella.

Delicately roll the cake without the towel this time. Refrigerate immediately.

Place the chocolate in a medium bowl.

In a small heavy saucepan, heat the cream and bring just to a boil.

Directly pour over the chocolate. Stir in the sugar and butter. Set aside.

Allow the ganache to cool down completely.

Evenly drizzle the ganache on top of the Swiss roll. Refrigerate for a minimum of 3 hours.

The cake can be decorated with banana slices upon serving. Enjoy!