Preheat oven to 350°F.

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 until the cake meets the toothpick test (stick a toothpick in and it comes out clean).

Cool on wire racks for 15 minutes and then turn out the cakes onto the racks and allow to cool completely.