"Why this recipe works:Beyond Red Velvet Cake’s shocking bright color, there’s something more—an extra-tender cake and fluffy cream cheese frosting, which we achieved by using a two unexpected ingredients: buttermilk and vinegar. They reacted with our recipe’s baking soda to create a fine, tender crumb. We also zeroed in on the perfect amount of cocoa that would add a dark hue to our Red Velvet Cake with Cream Cheese Frosting recipe and also lend it a pleasant cocoa flavor...."