Put honey, eggs, sugar and salt in a thick-bottomed saucepan and mix thoroughly.
Add butter cut into pieces and baking soda and heat (do not boil!) the honey mix slowly in a water bath, stirring, until the butter and sugar have dissolved and the mix has become a lighter color. (It took about 5 minutes for me).
Take the honey mix off the heat and let it cool to lukewarm.
Mix about 420 g of flour with cocoa powder, add it to the honey mix and knead it into a soft chocolate dough, adding the remaining flour in portions as needed if the dough is sticky.
Divide the dough into 10 equal pieces.
First roll one piece of dough in flour, roll it out thinly on a sheet of baking paper and cut out an approx. Ø 24 cm round cake layer from it. Put the dough scraps aside for the time being.
Pull the baking paper with the cake layer onto a baking tray, pierce the cake layer several times with a fork and bake it in a preheated oven at 356 °F (180 °C) for about 5 minutes.
Roll out the remaining 9 pieces of dough, cut out round cake layers and bake them in the same way one after the other. Let all 10 cake layers cool down.
Also roll out the leftover dough thinly, bake it, let it cool and crumble it finely.