First, beat the egg whites with a mixer until snow-like. While stirring nonstop, pour in the powdered sugar gradually. You have to obtain a mixture just like the kind used for meringues. Then add the walnuts, now begin stirring with a wooden spoon. Divide the resulting mixture into 4 parts, you'll be baking the layers from these.
Cover the bottom of a tray with baking paper. Using a spoon, spread out the 1st part of the mixture and bake a layer until browned. Take the layer out of the oven and leave it aside to cool. Repeat this for the rest of the mixture to obtain the 4 layers.
Once the layers are baked, begin preparing the cream. For it, first beat the yolks well with the soft butter using the mixer. Add the powdered sugar and beat again. Then add the remaining products for the cream.
Once everything is ready, it's time to assemble the cake. Carefully remove the baking paper from the now-cooled layers. You have to be careful so that the layers don't crumble.
Place 1 layer in a cake platter. Pour part of the prepared cream on top. Continue in this order until you've placed all 4 layers. At the very top, finish off with the last part of the cream, while smearing the sides as well. Put the cake away in the fridge to harden.
Once it has, melt the chocolate in a water bath, pour it over the cake, sprinkle ground walnuts on top and on the sides.
Put away in the fridge to harden again. Bon appetit!