Preheat oven to 350°F (175°C). Grease and flour two 9-inch round cake pans.

In a mixing bowl, combine flour, sugar, cocoa powder, baking powder, baking soda, and salt.

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

Stir in boiling water until the batter is smooth.

Pour the batter into the prepared pans and bake for 30-35 minutes, or until a toothpick comes out clean.

While the cakes are cooling, prepare the frosting by beating together softened butter, cocoa powder, and powdered sugar.

Add milk and vanilla, beating until smooth and creamy.

Once the cakes are completely cool, frost the top of one cake layer, place the second layer on top, and frost the top and sides.