For dough, mix together 15 eggs, 300 grams plain flour, 300 grams sugar, 1 tbsp baking powder and 2 tbsp cocoa powder and knead into fine dough. Place in an oven for 15 minutes at 220 c. For topping, mix 200 grams white butter, ½ cup fresh cream, 2 tbsp cocoa powder and 4 to 5 tbsp icing sugar and mix. Keep the mix in refrigerator. Melt 300 grams chocolate and mix with 1 ½ cup fresh cream and 3 to 4 tbsp butter cream to form a paste. Also make 1 cup sugar syrup and keep aside. When your sponge is ready, make a layer of sugar syrup in the middle of sponge. Coat with butter cream and make a layer of cooking chocolate on the top. Garnish with remaining butter cream and cut into rectangles of your preferred size.