Preheat oven to 350º F (176ºC).
Thoroughly grease and lightly dust (1 tablespoon of flour mixed with 1 tablespoon of cocoa powder) two 9-inch round cake pans and tap out excess.
In a medium bowl, combine flour, sugar, cocoa powder, salt, baking soda, and baking powder.
In a large bowl, use an electric mixer to beat oil, buttermilk, eggs, and vanilla.
Add the dry ingredients from the medium bowl, combine and mix on low speed. Don’t overmix.
Add water and mix again to combine it all together. Don’t overmix. Don’t worry, the batter will be thin.
Pour the batter into the pans and bake for 25 minutes or just until a toothpick/fork poked into the center comes out clean.
Cool for 10 minutes before removing cakes from the pans. Run a knife along edges of cake pans to release cakes.