Preheat the oven to 350°F (175°C). Grease and flour two 9-inch round cake pans.
In a large bowl, whisk together the flour, sugar, cocoa powder, baking powder, baking soda, and salt.
In another bowl, combine the buttermilk, oil, eggs, and vanilla. Mix until well combined.
Add the wet ingredients to the dry ingredients and mix until just combined. Slowly pour in the boiling water, mixing until smooth.
Divide the batter evenly between the prepared pans and bake for 30-35 minutes, or until a toothpick inserted comes out clean.
Allow the cakes to cool in the pans for 10 minutes, then turn them out onto a wire rack to cool completely.
Prepare the frosting by combining the coconut, pecans, heavy cream, and melted chocolate in a bowl.
Once the cakes are completely cool, spread a layer of frosting between the two layers and on top of the cake.
Allow the cake to set for 30 minutes before serving to let the frosting firm up slightly.
