2 1/2 cups sifted cake flour
2 tablespoons cocoa powder (unsweetened)
1 1/2 cups sugar
1 teaspoon baking powder
1 teaspoon salt
2 oz. red food coloring
1/2 cup unsalted butter, at room temperature
2 eggs, at room temperature
1 teaspoon vanilla extract
1 cup buttermilk, at room temperature
1 teaspoon white vinegar
1 teaspoon baking soda
1. Preheat oven to 350 degrees.
2. Sift altogether the cake flour, baking powder, cocoa 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, beat butter and sugar together until light, fluffy, and well incorporated. Beat in eggs, one at a time, then beat in vanilla and the red food coloring. Add a third of the dry mixture to the wet 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.
4. Butter and flour two 9-inch round cake pans or three 8-inch round cake pans.
5. Mix vinegar and baking soda in a small bowl and add it to the cake batter, stir well. Divide the batter between the cake pans and place them in a preheated oven. Bake for 20 to 25 minutes. Check halfway or so. Cake is done when a toothpick inserted in the center comes out clean.
5. Cool the cakes (still in the pans) on a wire rack for about 10 minutes or until fully cooled. 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.
6. Frost with cream cheese icing or buttercream icing.
Recipe Notes: I substituted skimmed milk with full cream milk and vinegar.