Preheat a fire or a charcoal grill. Let the fire or grill burn out to coals.
Spray a 12-inch Dutch oven with cooking spray. In a large bowl, combine sugar, flour, cocoa, baking soda, baking powder, and salt. In a medium bowl, combine eggs, oil, buttermilk, water, and vanilla. Pour the liquid ingredients into the dry ingredients. Stir with wire whisk until well mixed, about 2 minutes. Batter will be runny. Place 8 coals under the Dutch oven and 16 coals on the lid, bake in Dutch oven about 50 minutes, or until cake starts to pull away from the sides of the pan. Allow to cool for about 10 minutes. Remove cake from Dutch oven by placing cooling rack on top of Dutch oven and flipping oven over. Remove Dutch oven. Cool cake. When completely cool, cut into 2 layers. You can use dental floss to cut the cake.
Make ganache by combining all ganache ingredients in a medium-sized bowl. Stir until well mixed. Ganache will be about as thick as frosting. If it is too thick, thin with a little cream or milk. Spread onto cut layer. Top with other layer, cut side down.
Make glaze by combining melted chocolate with whipping cream. Drizzle over top of cake and allow to run down sides. Garnish with fresh raspberries and chocolate curls. Sprinkle with powdered sugar, if desired.
Recipe courtesy of Ruth Kendrick