Preheat oven to 350°F (175°C) and prepare two 9-inch round cake pans by greasing them or lining with parchment paper.

In a medium saucepan, combine 1 cup of unsalted butter, 1 cup of water, and ¾ cup of unsweet dark cocoa powder. Heat over medium until melted.

In a large bowl, whisk together 2 cups of all-purpose flour, 1 cup of light brown sugar, 1 teaspoon of baking soda, and ½ teaspoon of sea salt.

Pour the cooled cocoa mixture into the dry ingredients and mix gently with a spatula.

Add in 1 cup of buttermilk, 2 large eggs, and 1 teaspoon of vanilla extract. Stir until smooth.

Divide batter into pans and bake for 30-35 minutes or until a toothpick comes out clean.

Cool cakes in pans for 10 minutes, then invert onto a wire rack to cool completely.

Whip 1 cup of heavy cream until stiff peaks form, then fold in 1 cup of semisweet chocolate chips.

Blend 8 ounces of cream cheese, 4 ounces of melted white chocolate, and ½ cup of confectioners’ sugar until smooth.

On a serving plate, layer the cake, spreading mousse and cream cheese mixture alternately until finished.

In a saucepan, heat 1 cup of chocolate chips, ½ cup of heavy cream, and 1 tablespoon of sunflower oil, stirring until smooth.

Pour ganache over the cake and let it set for 15-20 minutes.

Pipe frosting around the base and garnish with chocolate truffles and rolled cookie wafers.