Preheat oven to 350F. Spray three 8-inch cake pans with a non-stick baking spray. Put an 8-inch parchment circle on the bottom and spray again.
In a mixing bowl, sift flour, baking powder, baking soda, and salt together. Set aside. Using a mixer, beat the butter, oil, and sugar together for 3 minutes on high.
3 ½ cups All-purpose flour, 2 ½ teaspoon Baking powder, 1 teaspoon Salt, 1 cup Unsalted butter, 1 ½ cups White granulated sugar, 3 tablespoon Oil
Add in sour cream and vanilla. Mix on medium until fluffy. Add in eggs and mix on medium until combined. Scrape the bowl to make sure the butter is all mixed in.
½ cup Sour cream, 1 tablespoon Pure vanilla extract, 4 Large eggs
Add in ⅓ of the dry ingredients and half of the buttermilk on low speed. Then, add another ⅓ of the dry ingredients and the rest of the buttermilk. Next, add the rest of the dry ingredients. Mix until just combined.
1 cup Buttermilk
Pour the batter evenly into the three pans. Place 5 cookie dough discs per cake pan. Place it on top of the batter.
Bake for 25-30 minutes. Bake until a toothpick inserted comes out clean.
Let the cake sit in the hot pans for 10 minutes. Then, transfer cake onto a wire rack to cool completely.