Finely chop the chocolate in the blitz chopper. Beat 4 egg whites with approx. 2 tablespoons of cold water until very stiff. Let sugar and vanilla sugar trickle in while continuing to beat. Carefully fold in 4 egg yolks. Fold in the almonds, chopped chocolate and lemon zest (or 1/2 bottle of lemon flavor).
Pour the dough into a greased pan and sprinkle with breadcrumbs on the bottom.
Bake in the oven at 175 ° C top / bottom heat (convection: 150 ° C / gas: level 2) for about 35-45 minutes (no preheating necessary!). Do a test with a toothpick, but remember that the chocolate is naturally soft when hot.
Let cool in the tin, remove and dust with powdered sugar.
Note: This cake is very rich and juicy because of the chocolate. It is very suitable for decorating with couverture, etc., because it is smooth and firm on the surface.