Preheat oven to 350 degrees
Line 2 9 inch cake pans with parchment paper
In large bowl sift together the flour, sugar, baking soda, salt and cocoa powder.
In large electric mixer bowl fitted with paddle attachment, combine oil, buttermilk, eggs, food coloring, vinegar and vanilla.
Mix on medium speed until thoroughly combined.
Turn mixer to low speed and slowly add sifted dry ingredients. Use rubber spatula to scrape down sides of bowl and make sure all dry ingredients are incorporated into wet.
Divide batter evenly among round cake pans.
Rap pans on counter to let extra air bubbles escape.
Place in oven and bake for approximately 30 minutes. Check for doneness by inserting a wooden toothpick/skewer in center of cake. It should come out clean.
Remove from oven and cool completely before frosting.