Preheat your oven to 350°F (175°C). Grease and flour three 9-inch round cake pans.

Pour boiling water over chopped chocolate in a bowl and stir until melted. Let cool slightly.

Cream together softened butter and granulated sugar until light and fluffy. Add eggs one at a time, mixing well after each. Stir in vanilla extract.

In a separate bowl, mix together flour, baking soda, baking powder, and salt. Add this dry mixture to the butter mixture alternately with buttermilk, starting and ending with the flour mixture. Stir until just combined.

Carefully stir in the melted chocolate until evenly distributed.

Divide the batter evenly across prepared pans and bake for 30-35 minutes. Check with a toothpick for doneness.

Let cakes cool in the pans for 10 minutes before transferring to wire racks to cool completely.

Combine chopped pecans, shredded coconut, sugar, egg yolks, and milk in a saucepan. Cook over medium heat, stirring constantly until thickened. Remove from heat and stir in vanilla extract.

Once cakes are cool, frost between layers and on top with the coconut-pecan frosting.