Prepare the chocolate sponge cake for the recipe, link for the sponge cake is provided above. Slice the cake into two even pieces.
Toast hazelnuts in an oven for about 10 minutes at 350F.
Combine together dulce de leche (cooked condensed milk), cream cheese, butter and nutella. Whisk together in a blender until it's perfectly smooth.
To have a nicely clean plate, cover the sides with foil. Place the first layer and apply an even amount of cream to it.
Apply an even amount of hazelnuts on to each layer of cream.
Cover the cake with the remaining cream. Leave it refrigerating while you prepare the next step.
Heat whipping cream to a boil. Pour it over chocolate chips, let it sit for a few minutes and stir to combine. Continue stirring until the mixture is completely smooth. Let it cool to a room temperature.
Using a pastry or a zip lock bag, pipe the edge of the cake with chocolate, letting the drizzles go down the sides. Pipe some onto the middle and spread with a spatula.
Sprinkle some hazelnuts on the edges of the cake and place it in a refrigerator overnight or at least for several hours.