Preheat your oven to 350°F (175°C).

Grease and flour two 9-inch round cake pans.

In a large mixing bowl, whisk together the flour, cocoa powder, baking powder, baking soda, and salt.

In another bowl, combine the eggs, buttermilk, vegetable oil, and vanilla extract. Whisk until smooth.

Pour the wet ingredients into the dry ingredients and mix until just combined.

Stir in the boiling water until the batter is smooth.

Divide the batter evenly between the prepared pans.

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

Let cool in the pans for 10 minutes, then transfer to a cooling rack to cool completely.