Preheat oven to 350°F (175°C). Grease and flour two 9-inch round cake pans.
In a large bowl, sift together the flour, sugar, and cocoa powder.
In another bowl, mix the buttermilk, eggs, oil, vanilla extract, and red food coloring.
Combine the wet and dry ingredients, mixing until smooth.
In a small bowl, mix the baking soda and vinegar, then add to the batter and stir well.
Divide the batter evenly between the prepared pans.
Bake in the preheated oven for 30 minutes, or until a toothpick inserted into the center comes out clean.
Allow cakes to cool in the pans for 10 minutes, then remove to a wire rack to cool completely.