Pre-heat oven to 350F. Prepare cake pans with non-stick spray or other pan release method.
In a large bowl combine flour, cocoa powder, baking soda, and salt. Whisk to combine and sit aside.
In the bowl of your mixer (or another large bowl if using a hand mixer), add oil and sugar. Mix to combine. Next add eggs, mix. Add buttermilk, vanilla, vinegar, and gel coloring. Mix really well to combine eggs and food coloring.
Add dry ingredients to the wet mixture. Mix batter for about 2 minutes on medium speed.
Divide batter evenly into prepared cake pans.
Bake for 30-35 minutes. Your cakes are done when the middle springs back when you press them, or if a toothpick can be inserted and comes out clean.
Remove the cakes from the oven and allow them to cool in the pan for about 5 minutes. After removing from the pan allow to cool completely before frosting.