Whip the cream, previously cooled from the refrigerator.
In a large bowl, beat the eggs and sugar for about 15 minutes with an electric mixer.
Sift the flour type 00 and hazelnut flower and baking powder and add it to mixture along with the vanilla. Finally, add the whipped cream folding from bottom to top.
Bake the sponge cake in a preheated oven for 30 minutes at 180C; then, another 20 minutes at 160C.
For the top layer, repeat the recipe by reducing the dose in half, for a mold of 18cm in diameter/10cm tall. Each sponge cake will be cut into three equal parts.
Pour the cream into a saucepan and cook over low heat. As soon as it starts to boil, remove from heat and add the chocolate and melt it. The mixture should be smooth and consistent. Let it cool.
With a spatula, stuff the milk chocolate ganache inside the cake and spread it over the outside. Melt some white chocolate in a double boiler and drizzle on the cake, covering it.
Place the top layer on the base and finish decorating with Ferrero Rocher around the base of the cake.