Preheat the oven to 350°F. Spray two 6-inch cake pans with baking nonstick spray. Line the bottoms with 6-inch parchment paper circles. Spray again.
In a medium bowl, sift the flour. Add in baking powder, baking soda, and salt. Set aside.
1 ¾ cup All-purpose flour, 1 teaspoon Baking powder, ½ teaspoon Baking soda, ½ teaspoon Salt
Using a mixer, beat the butter, oil, and sugar on high speed for 3 minutes. It will be light in color. Add in sour cream and vanilla. Mix on medium speed until combined. Scrape the bowl.
7 tablespoon Unsalted butter, 1 tablespoon Oil, ¾ cup White granulated sugar, ¾ tablespoon Pure vanilla extract, ¼ cup Sour cream
Add in the eggs and mix in on medium-high speed. Add eggs one at a time. Beat on medium for 1 minutes.
2 Large eggs
Add in ⅓rd of the dry ingredients and half of the buttermilk. Mix in on low. Add in another ⅓rd of the dry ingredients and the rest of the buttermilk. Finish with the rest of dry ingredients.
½ cup Buttermilk
Pour the batter evenly into the two cake pans.
Bake for 25-30 minutes. Bake until a toothpick inserted comes out clean. Let the cakes sit in the hot pans for 10 minutes. Then, transfer to a cooling rack to cool completely.