Beat the egg yolks on low heat in a water bath with half the sugar. Once it turns white, remove it from the heat. Beat the egg whites to a firm snow and add the remaining sugar to them. Combine the cooled yolks with the whites. Gradually add ground walnuts, flour, cocoa and mix with a wooden spoon.
Pour the resulting fluffy mixture into a form with baking paper. Bake it in a moderate oven until ready. Once the layer cools completely, cut it into 3 separate layers carefully. Make a sugar syrup from 4/5 cup (200 g) sugar, 3 1/3 tbsp (50 ml) rum and 4/5 cup (200 ml) water by boiling them together.
For the cream, beat the eggs with the sugar in a water bath in a container on the stove. Be careful not to cook them. Once they are done, remove them from the heat and continue whipping until cool. Separately, beat the butter into fluffy cream. Add the egg yolks to it tablespoon by tablespoon and mix well.
Finally, add the melted but cooled chocolate and mix until uniform. In an appropriate tray, place the first layer, soak it with sugar syrup, spread it with cream and so on until done. Smear the entire cake with cream.
Make a decoration as desired.