Roughly chop the chocolate. Cream fat, salt, vanillin sugar and sugar. Stir in eggs one after the other. Mix flour, baking powder and cocoa. Alternately stir in the milk, fold in the chocolate. Put the dough into a greased, flour-sprinkled square springform pan (24 x 24 cm) and smooth it down. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for 30-35 minutes.
Let it cool down on a cake rack in the tin. Coarsely chop the macadamia nuts and mix with the other nuts. Quarter the cake plate, cut each piece into quarters again to make 16 triangles. Chop the chocolate coating. Heat the cream, remove from the heat, melt the chocolate coating in it. Coat the surface of the cake corners with the cream and sprinkle with nuts, let dry