Preheat oven to 350F. Spray three 8-inch cake pans with baking non-stick spray. Place an 8 inch parchment circle on the bottom of the pans and spray again. Set aside.
In a medium bowl, sift the flour, baking powder, baking soda, and salt.
3 ½ cups Cake flour, ¼ cup Cornstarch, 2 teaspoon Baking powder, 1 teaspoon Baking soda, 1 teaspoon Salt
Using a mixer, beat the butter, oil, and sugar on high speed for 2 minutes. It will become pale in color.
1 cup Unsalted butter, 1 ½ cups White granulated sugar, 3 tablespoon Oil
Add in sour cream, vanilla, and eggs. Mix on medium until combined.
4 Large eggs, 1 tablespoon Pure vanilla extract, 1 cup Sour cream
Add in half of the flour and half of the buttermilk. Mix on low speed until starting to combine. Add in the rest of the flour and buttermilk and mix on low until just combined.
1 cups Buttermilk
Separate the batter into the three bowls. Bake for 21-24 minutes until a toothpick inserted comes out with moist crumbs.
Let cake cool in the hot pan for 10 minutes before transferring to a cooling rack. Allow cake to cool completely before decorating.