Preheat the oven to 350°F (175°C). Grease and flour a 9x13-inch baking pan.

In a large mixing bowl, combine the flour, sugar, baking powder, baking soda, salt, and cocoa powder. Whisk until well blended.

Add the eggs, milk, vegetable oil, and vanilla extract to the dry ingredients. Beat on medium speed for 2 minutes until smooth.

Stir in the boiling water until fully combined; the batter will be thin. Pour the batter into the prepared baking pan.

Bake for 30-35 minutes or until a toothpick inserted in the center comes out clean.

Remove the cake from the oven and let it cool in the pan for about 15 minutes. Using the handle of a wooden spoon, poke holes all over the cake, about 1 inch apart.

In a small bowl, mix the sweetened condensed milk with the shredded coconut and chopped pecans. Pour this mixture evenly over the cake, allowing it to seep into the holes.

Let the cake cool completely, then frost with chocolate frosting.

Serve chilled or at room temperature.