Preheat oven to 350 degrees Fahrenheit. Butter three 9-inch cake rounds. Dust with flour and tap out the excess.
Mix together flour, sugar, cocoa, baking soda, baking powder, and salt in a stand mixer using a low speed until combined.
Add eggs, buttermilk, warm water, oil, and vanilla. Beat on a medium speed until smooth. This should take just a couple of minutes.
Divide batter among the three pans. I found that it took just over 3 cups of the batter to divide it evenly.
Bake for 30-35 minutes in a 350 degree oven until a toothpick inserted into the center comes out clean.
Cool on wire racks for 15 minutes and then turn out the cakes onto the racks and allow to cool completely.
Frost with your favorite frosting and enjoy!