Heat the white chocolate and mascarpone in a water bath. Stir the unflavored gelatin powder into the chocolate mascarpone mixture, let it cool, and then fold in the whipped cream. Divide the cream between two bowls and add the cocoa powder to one bowl for the dark chocolate cream. Then chill both creams in the refrigerator.
Cream the eggs and sugar. Combine the dry ingredients and work them into the egg and sugar mixture, followed by the milk, vegetable oil, and hot water. Pour the batter into a greased cake pan and bake in a preheated oven set to 350°F for 45 minutes. Once the cake has cooled, cut it in half horizontally.
Cut the 2 slices in half vertically so you are left with 4 equal rectangles.
Spread the white chocolate cream over 3 of the 4 rectangles and stack them on top of each other to create the bottom part of the treasure chest.
Use the dark chocolate cream to glue Kit Kat bars all around the lower part of the treasure chest cake. Spread dark chocolate cream over the top layer of chocolate cake. Cover all the corners and the points where the Kit Kat bars meet the treasure chest cake with chocolate Twizzlers.
Heat a fork with a lighter and melt a keyhole into a large chocolate square, then glue it to the front of the treasure chest cake with some dark chocolate cream.
Using more of the dark chocolate cream, glue a sour candy belt to either side of the treasure chest cake. Use a bottle cap to cut out circles from another chocolate square and glue the circles right next to the handles with the dark chocolate cream.
Sprinkle Graham cracker crumbs around the base of the treasure chest cake and sprinkle gold sanding sugar on top of the cake. Then stick wooden skewers into the cake for the next step.
Heat the marshmallows and butter in a water bath and stir in the Rice Krispies cereal. Mold the Rice Krispies mixture around a greased loaf pan and wait until it has cooled and set.
Decorate the lid with dark chocolate cream, Kit Kat bars, and chocolate Twizzlers. Cover the inside of the treasure chest with chocolate gold coins and then carefully lower the lid onto the wooden skewers – and the most magical chocolate cake ever is done!
