1. Preheat oven to 350 degrees. Butter and flour two 9-inch round cake pans or three 8-inch round cake pans.
2. Sift together the cake flour, baking powder, and salt into a medium bowl; set aside. In a small bowl, mix food coloring and cocoa powder to form a thin paste without lumps; set aside.
3. In a large bowl, using a hand mixer or stand mixer, beat butter and sugar together until light and fluffy, about three minutes. Beat in eggs, one at a time, then beat in vanilla and the red cocoa paste, scraping down the bowl with a spatula as you go. Add one third of the flour mixture to the butter mixture, beat well, then beat in half of the buttermilk. Beat in another third of flour mixture, then second half of buttermilk. End with the last third of the flour mixture, beat until well combined, making sure to scrape down the bowl with a spatula.
4. Make sure you have cake pans buttered, floured, and nearby. In a small bowl, mix vinegar and baking soda. Yes, it will fizz! Add it to the cake batter and stir well to combine. Working quickly, divide batter evenly between the cake pans and place them in a preheated 350 degree oven. Bake for 25-30 minutes. Check early, cake is done when a toothpick inserted in the center comes out clean.
5. Cool the cakes in their pans on a wire rack for 10 minutes. To remove the cakes from the pan, place a wire rack on top of the cake pan and invert, then gently lift the pan. Allow cakes to cool completely before frosting. Frost with buttercream or cream cheese icing (recipe below).
Recipe Notes: *Sift cake flour once before measuring, then sift again with the other dry ingredients per recipe instructions. Wear an apron and be careful with the red food coloring–no matter how hard I try, I always end up staining something! As you’re mixing the cake batter, use a spatula to scrape down the bowl frequently throughout the entire process.
Cream Cheese Frosting
16 oz. cream cheese (2 packages), softened
1/2 cup unsalted butter (one stick), softened
1 teaspoon vanilla extract
2 1/2 cups powdered sugar, sifted
pinch of salt
With an electric mixer, blend together cream cheese and butter until smooth. Turn mixer to low speed and blend in powdered sugar, salt and vanilla extract. Turn mixer on high and beat until light and fluffy. Use immediately or refrigerate, covered, until ready to use. If refrigerated, the frosting will need to be brought to room temperature before using (after frosting softens up, beat with mixer until smooth).
Recipe Notes: If you prefer a sweeter and/or stiffer frosting, more powdered sugar can be added (up to four cups). But remember, the more sugar you add, the less you’ll be able to taste the tangy cream cheese!