Preheat your oven to 350°F (175°C) and grease the 9-inch round cake pan.
In a mixing bowl, sift together the flour, cocoa powder, sugar, baking powder, baking soda, and salt.
In a separate bowl, beat the eggs, then add the buttermilk, vegetable oil, and vanilla extract. Mix well.
Now slowly incorporate wet ingredients into the dry ingredients and combine until the batter is smooth.
Incorporate the boiling water until the batter is thoroughly mixed.
Transfer the batter to the greased cake pan and place it in the oven to bake for 30-35 minutes, or until a toothpick inserted into the center emerges clean.
Let the cake cool on a cooling rack before serving.