For the sponge cake

1. In a large bowl, or in the bowl of a stand mixer, add the eggs, the sugar, and the vanilla.
2. With a hand held mixer, or in the stand mixer fitted wiyh the whisk attachment, whip the mixture for 15 minutes, no less. It has to be light and fluffy, 4-5 times the volume that it was.
3. Preheat the oven at 180°C/350°F. I used convection bake at 170°C/340°F.
4. Sift the flour on a parchment paper.
5. Add it to the whipped mixture in two batches, and mix with a spatula or whisk with movements that go from top to bottom, not circular, just enough to obtain a smooth mixture.
6. Pour in a buttered baking pan (20 cm/8") and do not tap the pan nor smooth the surface.
7. Bake in the preheated oven for about 25 minutes.
8. Take out of the oven, let cool for a few minutes in the pan, then unmold, and turn the sponge cake upside down on a rack to cool completely.
9. Lastly, wrap well in plastic and refrigerate until the next day to cut and assemble.

For the mascarpone cream

1. In a large bowl, with a handheld mixer beat the whipped cream on high, and slowly add the icing sugar and vanilla. Beat until almost firm but do not overwhip. Add the mascarpone and fold in with a spatula or beating on low speed.

Assembly

1. With a long, serrated knife, cut the sponge cake into 2 layers.
2. Have the mascarpone cream, cocoa powder, and coffee/liquor ready.
3. Place the bottom of the first layer on a plate with a little bit of coffee to soak the bottom, then place it in an 8" baking pan (springform or with removable bottom).
4. Brush the top with the coffee, making sure to soak it well.
5. With an offset spatula, spread the mascarpone cream on top, leveling it well. Dust with cocoa powder and grate some dark chocolate.
6. Again, soak the inside of the second disc of sponge cake in the plate with coffe. Then, place it on top of the first layer. Brush the top of the sponge with coffee and then spread the last of the mascarpone cream.
7. Finish it with a dusting of cocoa powder and more grated dark chocolate.
8. Refrigerate for at least 3 hours. The next day it is even better.
9. To remove the cake from the pan with a removable bottom: first, with a thin knife, delicately go around the edges to release the cake from the sides. Then, place the pan on top of an inverted bowl tall enough to release the cake from the pan and making sure the diameter is smaller than the cake pan. Gently pull down the ring and lift the cake off the bowl. Lastly, with a wide spatula, slide it in between the cake and the bottom of the pan and slide it onto the serving platter.