Step 1

Add semi-sweet chocolate chips and butter to a bowl. Pour boiling hot whipping cream over the mixture and set aside for 5 minutes, then stir well using a whisk to get a smooth mixture. Place in the fridge for 4 hours, or overnight.

Step 2

Line a 25 cm x 35 cm (9 x 13-inch) baking sheet with parchment paper, then grease the paper with butter. Evenly dust with flour, then remove any excess flour from the pan. Preheat the oven to 180 °C / 350 °F.

Step 3

Make the sponge cake. Add flour, baking powder, and cocoa powder to a small bowl. Add the eggs, sugar, and a pinch of salt to a large bowl. Using an electric mixer, beat the egg mixture until pale in color and tripled in size. Mix for about 5 - 8 minutes. Then gradually add the dry ingredients while beating on medium speed. It shouldn't take more than a minute. Pour in the olive oil and milk, and fold in with a spatula.

Step 4

Pour the sponge cake batter into the prepared baking sheet. Spread the mixture evenly using a spatula. Transfer to the preheated oven on the middle rack. Bake for 14 - 16 minutes at 180 °C / 350 °F.

Step 5

Transfer the freshly baked swiss roll with the parchment paper on a damp towel while the swiss roll is still hot. Carefully and gradually start removing the parchment paper while gently rolling the sponge cake into a swiss roll shape. Wrap the parchment paper around the cake, then wrap in a damp towel. Set aside for 30 minutes for the sponge cake to cool.

Step 6

Transfer the chocolate ganache from the fridge to a large bowl (room temperature) and start beating with an electric mixer. Mix for at least 5 minutes or until the ganache is smooth and creamy. In a separate, clean bowl, beat the whipping cream and sugar until stiff peaks form. Beat the whipped cream into the chocolate ganache, then fold the rest gently using a spatula. Try to keep volume.

Step 7

Unroll the chocolate swiss roll. Spread the chocolate ganache evenly over the surface, then roll tightly again and place in the fridge for at least 1 hour.

Step 8

Add the chocolate chips and butter to a bowl. Pour the boiling hot whipping cream over the chocolate and set aside for 5 minutes, then stir with a whisk to get a smooth mixture. Pour over the chocolate swiss roll. Set aside for the chocolate to set, then cut into slices and serve.