Prepare the Cake: Preheat your oven to 350°F (175°C). Grease and flour three 8-inch round cake pans.
In a large bowl, whisk together flour, sugar, cocoa powder, baking powder, baking soda, and salt.
Add buttermilk, oil, eggs, and vanilla. Mix until combined. Slowly stir in hot water until the batter is smooth.
Divide the batter evenly among the prepared pans. Bake for 30-35 minutes or until a toothpick inserted into the center comes out clean. Cool completely.
Make the Frosting: In a saucepan, combine evaporated milk, sugar, egg yolks, and butter. Cook over medium heat, stirring constantly, until thickened (about 10 minutes). Remove from heat, then stir in vanilla, coconut, and pecans. Let cool.
Assemble the Cake: Place one cake layer on a serving plate. Spread frosting on top. Repeat with the remaining layers, topping the final layer with frosting.
Serve and enjoy!