Preheat your oven to 350°F and prepare cake pans with grease and flour.
In a large bowl, whisk together flour, sugar, cocoa powder, baking powder, baking soda, and salt.
In another bowl, beat eggs and mix with buttermilk, oil, and vanilla extract.
Combine wet mixture with dry ingredients, then stir in boiling water.
Divide batter into pans and bake for 30-35 minutes until a toothpick comes out clean.
Cool cakes in pans for 10 minutes, then transfer to a wire rack.
Cook condensed milk and coconut in a saucepan until thickened, then cool.
Spread coconut filling on one cake layer and top with the second layer.
Heat cream, add chocolate, and stir to make ganache, then pour over the cake.
Let ganache set for 30 minutes before serving.