How to make
Prepare the layers by beating the egg whites with the sugar into foam, then adding the walnuts, cocoa and flour and stirring carefully with a spatula. This mixture is enough for making 4 layers.
Lay out a 10 (26 cm) diameter baking dish with baking paper and pour in part of the mixture, distribute it evenly along the bottom of the dish and put it to bake in a preheated 340°F (170 °C) oven.
The procedure is the same for the other 3 layers - divide up the mixture so that you have enough for all layers. They bake very quickly, so be careful not to burn them - it took me about 10 min. for each.
For the cream, pour the water in the pot and put it on the stove. Once it comes to a boil, add the crumbled chocolate, stir and add the cocoa. Once the chocolate melts and homogenizes, remove from the stove. Add the cognac and leave it to cool slightly.
Beat the butter with the sugar until creamy, then add the egg yolks 1 by 1 and finally pour in some of the chocolate mixture. Beat everything with a mixer until it becomes a homogeneous creamy mixture.
Leave the baked layers to cool well and only then carefully remove the baking paper.
Form the cake by smearing one layer with part of the cream, putting on the 2nd one, cream again and so on till you're done; be sure to smear with cream all over at the end. Leave it in the fridge for a few hours for the cream to harden.
To make the chocolate ganache, put the cream in a casserole on the stove. Add the chocolate to it before it comes to a boil, stir until fully homogenized.
Leave it in a cool area to cool and thicken and pour it over the cake. Optionally, decorate with coconut flakes, walnuts or almonds on top.