Preheat your oven to 350°F (175°C).

Grease and flour the two 9-inch round cake pans.

In a mixing bowl, whisk together 1 cup boiling water and 1 cup unsweetened cocoa powder until smooth.

In another bowl, sift together 2 1/2 cups all-purpose flour, 1 1/2 teaspoons baking soda, 1/2 teaspoon baking powder, and 1 teaspoon salt.

In a large mixing bowl, cream 1 cup softened unsalted butter and 2 cups granulated sugar until light and fluffy.

Add the 4 large eggs one at a time, mixing well after each addition, then blend in 1 teaspoon vanilla extract.

Gradually add the sifted dry ingredients to the creamed mixture, alternating with the cocoa mixture, mixing just until combined.

Pour the batter evenly into the prepared pans and bake at 350°F (175°C) for 30 minutes, or until a toothpick inserted in the center comes out clean.

Let the cakes cool in the pans for 10 minutes, then transfer to a wire rack to cool completely.

In a saucepan over medium heat, combine 1 cup evaporated milk, 1 cup granulated sugar, 1/2 cup unsalted butter, and 3 beaten egg yolks; stir constantly for about 10 minutes until thickened.

Remove the frosting from heat and stir in 3/4 cup shredded unsweetened coconut and 1 cup chopped pecans; let cool slightly.

Place one cake layer on a serving plate, spread a layer of frosting, top with the second layer, then frost the top and sides with the remaining frosting.