Make the caramelized sugar first so you don't have to pause later when assembling the cake. Melt the sugar and butter on the stove, spread out the resulting caramel in a suitable container to harden. Then blend it in a blender or mash in a mortar and pestle.
Start making the cake layers. Beat the eggs with the sugar to fluffy cream. Add the sifted flour and cocoa and beat to a smooth consistency. Then add the walnuts - set your mixer aside now and stir with a spatula.
Bake 2 layers (I baked in a 10 1/4″ (26 cm) diameter tray) in a preheated 356°F (180 °C) oven with removable sides, laid out with baking paper. Bake about 15 min. but do check with a toothpick because since the layers consist primarily of walnuts they bake a little quicker.
Start assembling the cake. Syrup the 1st layer with hot syrup consisting of 2 cups sugar and 1 cup water, smear with cream mixture (slightly less than 1/2) and sprinkle caramelized sugar. Place the 2nd layer, syrup it, smear the entire cake with the remaining cream mixture and sprinkle caramelized sugar and walnuts.