Preheat the oven to 350°F, grease 2X8 or 3X6 inch pans, and dust with flour set aside.
Sift all the dry ingredients, excluding the sugar, and set aside.
2½ cups All-purpose flour, 1 tablespoon Corn starch, ½ teaspoon Salt, 3 teaspoon Baking powder
Mix milk and the buttermilk, and set aside.
1 cup Milk, ¼ cup Buttermilk
With the stand mixer set on whisk attachment, whisk together the oil, eggs, vanilla extract, and the sugar until well combined. About 2-3 minutes.
2 Cups Sugar, ½ cup Oil, 1½ tablespoon Vanilla extract, 3 Eggs
Add in the sour cream and mix.
½ cup Sour cream
Using a spatula, add ⅓ of the dry ingredients alternating with the milk mixture. repeat this three times. Start and finish with the dry ingredients.
Put the bowl back on the stand mixer and whisk the batter for only 15 seconds. DO NOT OVERMIX.
Pour the batter into the prepared pans and bake for 25-28 minutes or until the insert comes out clean.
Let cool in the pan for 10 minutes and then transfer to a cooling rack. let cool completely before frosting.