Preheat oven to 350°F (175°C). Grease and flour three 9-inch round baking pans.
In a large bowl, stir together flour, sugar, cocoa, baking powder, baking soda, and salt.
Add milk, vegetable oil, eggs, and vanilla to flour mixture and mix together on medium speed until well combined. Reduce speed and carefully add boiling water to the cake batter. Beat on high speed for about 1 minute to add air to the batter.
Pour batter evenly into the prepared pans. Bake for 30-35 minutes, or until a toothpick inserted in the center comes out clean. Remove from the oven and allow to cool for about 10 minutes, remove from the pan and cool completely.
To make the frosting, combine evaporated milk, sugar, egg yolks, butter, and vanilla in a saucepan. Cook over medium heat, stirring constantly until thickened, about 12 minutes. Remove from heat and stir in coconut and pecans. Cool until thick enough to spread.
Frost the cake with the coconut-pecan frosting between layers, on top, and around the sides.
