First, preheat your oven to 350F.
Spray 3 round cake pans with cooking spray
Dust the pans lightly with flour, set aside.
In a Large mixing bowl or kitchenaid mixer combine the Flour, Hersheys cocoa, sugar, baking powder, baking soda, and the salt.
Add in the milk, oil, eggs and the vanilla extract & mix until everything is thoroughly incorporated. Once all combined, stir in the boiling water last; mix again, the batter will be very thin.
Pour the batter evenly in each of the sprayed/floured cake pans
Bake for 30-35 minutes, or until a toothpick inserted in the center of each layer comes out clean. Once fully baked, remove from oven & allow the 3 cakes to cool for at least 10-15 minutes before removing them.
Once removed, transfer to a wire rack to finish cooling completely.
I always use a cake leveler to make sure the layers are even, you can also use a serrated knife
While they finish cooling, prepare your frostings.