First, I'll make chocolate Genoise. Separate the egg into white and yolk. Place the yolk in a bowl and whisk in 50g of sugar. Keep whipping until the dough is heavy and ivory. Add vanilla extract to this and mix lightly.

Place the whites in another bowl and beat them without hesitation, then add the rest of the sugar to make a firm meringue. Add 1/3 of the meringue to the yolk dough and mix evenly,

Add the sifted powder and mix it with a rubber spatula. Add the meringue in two at a time and mix well with the chocolate dough.

Melt the butter in a medium hot water and mix with grape seed oil, then mix evenly with a rubber spatula, adding little by little to the dough. Place the dough in a mold with parchment paper, lightly strike it two or three times to remove air bubbles, and bake it in a preheated oven at 170 for about 30 minutes.

Cool the baked Genoese and slice them into 3 pieces. It's good to make syrup in advance and cool it down. Put sugar and water in a pot, bring to a boil until the sugar is completely dissolved, and cool. Allow to cool completely, then add the kalua and mix (optional)

Using a 15cm round mousse ring, cut the Xenuaz to fit the size of the mousse ring.

Shall we make sweet dark ganache now? Put whipped cream and oligosaccharide in a thick pot and bring to a boil. Remove from heat when it starts to boil, add dark chocolate and melt stirring.

When the dark chocolate is completely melted, add butter at room temperature and melt it while stirring. Now, let it cool enough to put it on the cake.

Place a sheet of Genuaz and spread syrup (50g of unrefined brown sugar, 70g of water, 1ts of kalua) evenly to moisten the sheet, and spread evenly on top of cooled ganache.

On top of that, place a sheet of Xenois and apply the syrup again. After putting the last Xenuaz, apply syrup, and spread thinly with ganache on the top and sides. It's hard to do this if the kanashu is too watery because it doesn't cool down, so it's good to cool it down before you work. When the thinly applied ganache hardens, heat the remaining ganache slightly and pour it over, leaving it to flow down naturally.