Preheat the oven to 350°F (175°C). Prepare two 9-inch round cake pans by greasing and dusting them with flour.

In a large bowl, combine all the dry ingredients (flour, sugar, cocoa powder, baking powder, baking soda, and salt) until well blended.

Add the eggs, milk, vegetable oil, and vanilla extract to the dry mixture and mix on medium speed for about 2 minutes until fully combined.

Carefully stir in the boiling water to the batter, noting how it transforms into a thin, silky mixture.

Pour the batter evenly into the prepared pans, ensuring there are no air bubbles, and bake for 30-35 minutes or until a toothpick inserted in the center comes out clean.

Allow the cakes to cool in the pans for 10 minutes, then transfer them to wire racks to cool completely.

For the frosting, combine the sweetened condensed milk, butter, shredded coconut, and chopped pecans in a medium saucepan over medium heat. Cook, stirring frequently until thickened and fragrant.

To assemble, place one cake layer on a serving platter, spread frosting on top, add the second layer, and cover the top and sides with the remaining frosting.