Combine the cake flour, cocoa powder, baking soda, and salt into a bowl. Stir together with a whisk until evenly combined. Set aside
In a large mixing bowl, add the the vanilla, buttermilk, eggs and oil and stir until combined
Add in the sugar and mix until combined
Add in the vinegar and food dye and stir until evenly incorporated
Once all the wet ingredients are incorporated, add in the dry ingredients. Stir until the mixture is just evenly combined
Once combined, add the hot water. The batter will be very thin
Pour the batter into 3 greased and floured 8-inch round cake pans and cook for ~30-40 minutes (ovens vary so test with a toothpick in the center and remove when it comes out clean) 350 F – make sure a toothpick comes out clean
Set aside to cool
Once cooled, ice the cake with cream cheese icing (recipe below)