Divide the phyllo dough sheets into 20 rectangles or squares of uniform size. Chop/grind the nuts and almonds to a coarse texture and mix together with the sugar, cinnamon, and lemon zest.
Place 10 rectangles of phyllo dough in a baking pan lined with parchment paper. Spread with chocolate and sprinkle the nut mixture, pressing it down firmly. Spread another layer of phyllo dough with chocolate spread and place it over the first layer with the chocolate side facing down.
Brush the dough with the beaten egg, sprinkle sugar and crushed pistachios (or sesame seeds), and bake until the dough achieves a beautiful brown color.
Place the syrup ingredients in a small pan or saucepan and boil for 3 minutes over high heat, then reduce for about 20 more minutes or until the syrup thickens. Immediately after the cake comes out of the oven, pour the syrup over the entire cake.