Preheat the oven to 375 F. Line 3 spring forms or 9 inch cake pans with parchment paper.

In a medium dish, combine flour, unsweetened cocoa powder, baking soda and baking powder. Set aside.

In a large dish, put butter, light brown sugar and granulated sugar. Mix until it gets light and fluffy, using medium speed.

Add eggs, one at a time, vanilla extract and milk and mix until creamy.

Slowly add dry ingredients and mix until well combined, using the minimum speed.

Divide it into 3 cake pans, already prepared. Bake for 9-10 minutes, until the toothpick comes out dry or with a few crumbs on it.

Take out of the oven and leave in the cake pan to cool and then transfer to a wire rack to cool completely.

CHOCOLATE MOUSSE – melt the chocolate, following the instructions given on the package and set aside. In a large bowl, mix heavy cream, with an electric mixer, at minimum speed, for about a minute, then mix some more, 3-4 minutes, at maximum speed, until it gets solid. Add vanilla, sugar and melted chocolate and mix until well combined.

CHOCOLATE GANACHE - Put heavy cream in the pan, on medium heat, and then remove from heat, before it comes to boil. Add chopped chocolate and cover it. Leave for 3 minutes for chocolate to melt and then mix all the ingredients until well combined and you get a fine chocolate ganache. .

CHOCOLATE BARK TO DECORATE – melt chocolate following the instructions given on the package and put it on the baking sheet lined with parchment paper. Spread the chocolate so to get a very thin layer, of about 0.08 inch. Put it in the fridge until firm for about 15 minutes. Take out of the fridge and cut into pieces, with a knife.

TO ASSEMBLE - Put parchment paper on the plate. Place 1 cake and spread evenly ⅓ of chocolate mousse. Repeat the same two more times and finally cover the whole cake with chocolate mousse. Spread chocolate ganache evenly on top of the cake. Decorate the sides of the cake with chocolate bark.

Cake should be made first, and then chocolate mousse.

Finally make chocolate ganache and chocolate for decoration.