Grease two 9-inch cake pans and line the bottom and sides with parchment paper. Preheat the oven to 325°F.

Sift together the all-purpose flour, cake flour, sugar, baking soda, baking powder, salt, and cocoa in a large bowl.

In the bowl of an electric mixer, blend the vegetable oil, buttermilk, eggs, red food coloring, white vinegar, and vanilla extract until well combined.

Gradually mix in the dry ingredients until smooth. Avoid over-mixing; as soon as the batter is lump-free, pour it into the prepared cake pans.

Bake at 325°F for 30-35 minutes, or until a wooden toothpick inserted in the center comes out clean.

Turn the cakes out onto a wire rack, remove the parchment paper, and let them cool completely.

For easier serving, you can cut each layer into four or leave them as two layers if preferred.

To make the frosting, mix the cream cheese, butter, vanilla extract, and icing sugar until smooth and fluffy. Add milk as needed to achieve a spreadable consistency.

If using toasted pecans, sprinkle ¼ cup over each layer of frosting as you assemble the cake.