Preheat oven to 350°F. Place the oven rack in the middle of the oven. Using nonstick cooking spray that contains flour, generously spray 3 -- 6 inch cake pans. Set aside.
In the bowl of a stand mixer whisk the cake flour, sugar, cocoa powder, baking soda, and salt.
In a separate bowl, or large liquid measuring cup, whisk the vegetable oil, sour cream, buttermilk, egg, vanilla extract, white vinegar, and black food coloring. Add the wet ingredients to the dry ingredients (using a paddle attachment) and mix on low until ingredients are combined.
Pour the batter into the three cake pans, use an off set spatula to spread the batter into an even layer. Tip: use a kitchen scale to ensure equal amounts of batter in each pan.
Place the cake pans in the oven and bake for 25-28 minutes. The cake is done when a toothpick inserted in the center comes out clean or with a few moist crumbs. (The cake will be more moist if you don't over bake it, so I like to remove it when the toothpick has moist crumbs on it-- but no wet batter). Remove from the oven and let the cakes cool in the pan for 10 minutes before turning out onto a wire rack to cool completely.