Preheat the oven to 350°F (175°C) and line a muffin tin with cupcake liners.

In a large mixing bowl, combine flour, sugar, cocoa powder, baking soda, baking powder, and salt.

Add softened butter, eggs, vanilla extract, and buttermilk. Mix until smooth.

Carefully stir in boiling water until well combined. The batter will be thin.

Pour the batter into the prepared muffin tin, filling each liner about 2/3 full.

Bake for 18-20 minutes or until a toothpick inserted in the center comes out clean.

Allow cupcakes to cool completely before frosting.

In a saucepan, combine evaporated milk, sugar, butter, and egg yolks. Cook over medium heat, stirring constantly until thickened.

Remove from heat and stir in coconut, pecans, and vanilla extract. Allow to cool before using.

Frost the cooled cupcakes with the coconut-pecan frosting.