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

In a large mixing bowl, whisk together the flour, sugar, cocoa, baking soda, baking powder, and salt until no lumps remain.

Add the buttermilk, vegetable oil, eggs, and vanilla extract to the dry ingredients.

Mix on medium speed with an electric mixer or whisk for 2 minutes until well combined.

Reduce speed and carefully pour in the boiling water. Stir by hand until the batter is smooth (batter will be thin).

Divide the batter evenly between the two prepared cake pans.

Bake for 30 to 35 minutes, or until a wooden toothpick inserted into the center comes out clean.

Cool the cakes in their pans for 10 minutes on a wire rack.

Run a knife around the edges and invert the cakes onto the racks to cool completely before frosting.