Preheat the oven to 350°F (175°C). Grease and flour the two 9-inch round cake pans.
In a large mixing bowl, combine the flour, sugar, cocoa powder, baking powder, baking soda, and salt. Whisk together until well combined.
Add the eggs, milk, vegetable oil, and vanilla extract to the dry ingredients. Using an electric mixer, beat on medium speed for about 2 minutes until smooth.
Carefully stir in the boiling water. The batter will be thin.
Pour the batter evenly into the prepared cake pans.
Bake in the preheated oven for 30 to 35 minutes, or until a toothpick inserted into the center comes out clean.
Once baked, remove the cakes from the oven and allow them to cool in the pans for about 10 minutes.
Transfer the cakes to a wire cooling rack to cool completely.
Once cooled, frost with your favorite chocolate frosting, and enjoy!