Preheat the oven to 350°F. Spray three 8-inch cake pans with baking nonstick spray. Line the bottoms of the pan with 8-inch parchment paper circles. Spray again.
In a mixing bowl, sift the flour. Add the baking powder, baking soda, and salt. Set aside.
3 ½ cups All-purpose flour, 2 teaspoon Baking powder, 1 teaspoon Baking soda, 1 teaspoon Salt
Using a mixer, beat the butter, oil, and sugar on high speed for 3 minutes. It will be light and fluffy. Add the sour cream and vanilla and mix on medium until combined. Scrape the bowl.
¾ cup Unsalted butter, ¼ cup Oil, 1 ½ cups White granulated sugar, ½ cup Sour cream, 1 tablespoon Pure vanilla extract
Add the eggs one at a time on medium speed. Switch to high speed and beat for 1 minute.
4 Large eggs
Add ⅓rd of the dry ingredients and half of the buttermilk and mix on low speed. Add another ⅓rd of the dry ingredients and the rest of the buttermilk. Finish with the rest of the dry ingredients. Mix until just combined. Don't over mix. Scrape the bowl
1 cup Buttermilk
Pour the cake batter evenly throughout the three cake pans. Bake for 22-25 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. Cool the cake layers completely.