Preheat your oven to the appropriate temperature for baking.
In a large mixing bowl, combine the all-purpose flour, granulated sugar, cocoa powder, baking soda, baking powder, and salt. Mix well to ensure all dry ingredients are evenly distributed.
Add the eggs, buttermilk, vegetable oil, and vanilla extract to the dry mixture. Beat the mixture until it is smooth and well combined.
Carefully stir in the boiling water until the batter is fully incorporated. The batter will be quite thin.
Pour the batter into prepared baking pans and bake until a toothpick inserted in the center comes out clean.
While the cake is baking, prepare the frosting by creaming the softened unsalted butter in a bowl until it is light and fluffy.
Gradually add the powdered sugar and cocoa powder to the butter, mixing until smooth.
Finally, mix in the vanilla extract until everything is well combined and the frosting is ready to use.
Once the cake has cooled, spread the frosting evenly over the top and sides of the cake.
