Mix the sugar, egg yolks and butter well until frothy. Mix in the nuts, flour, baking powder, cinnamon, lemon baking and salt into the first mixture. Beat the egg white until stiff and fold into the batter, then fold in the chocolate flakes. Grease a loaf pan, pour in the mixture and bake in a preheated oven at 180 ° C for 60 minutes.
Turn the cake out of the pan, let it cool down a little, liquefy the couverture and coat the cake with it.