Chocolate is melted in a water bath with the butter. Egg whites were separated from the yolks. Whip with a mixer with 1 tsp sugar and limontozuto. When almost harden, slowly add the remaining sugar, without stopping stirring. Yolks are broken down in a separate bowl, mix with the chocolate carefully. Add successively the walnuts, sifted flour and cinnamon. Add egg white, stirring up the bottom. The whole mixture was poured into a tray with 22 cm diameter, the bottom of which is covered with oiled paper (foil). Bake 25 minutes in preheated 175 C oven. Readiness check with a toothpick. Cake to cool in the pan and then turns into dessert plate. Sprinkle with cocoa.