Preheat your oven to 350°F. Grease and flour two 9-inch round cake pans, then line the bottoms with parchment paper circles to prevent sticking.
In a medium bowl, whisk together the flour, sugar, baking soda, salt, and cocoa powder until they are fully combined and no streaks remain.
In a large separate bowl, vigorously whisk the oil, buttermilk, eggs, food coloring, vanilla extract, and vinegar until the mixture is completely smooth and uniformly bright red.
Gradually add the dry ingredients to the wet ingredients, stirring with a spatula just until the flour is fully incorporated and no dry pockets remain; be careful not to overmix the batter.
Divide the batter evenly between the two prepared pans and bake for 25 to 30 minutes, or until a toothpick inserted into the center of the cakes comes out clean with a few moist crumbs attached.
Let the cakes cool in their pans on a wire rack for 10 minutes, then carefully invert them onto the rack, peel off the parchment paper, and allow them to cool completely before frosting.