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, 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, 1 tablespoon Baking powder, 1 teaspoon Salt, ¾ cup Unsalted butter, 1 ½ cups White granulated sugar, ¼ cup Oil
Add in sour cream and vanilla. Mix on medium until fluffy. Add eggs one at a time. Mix until combined. Scrape the bowl to make sure the butter is all mixed in.
½ cup Sour cream, 2 tablespoon Pure vanilla extract, 4 Large eggs
Add in ⅓ of the dry ingredients and half of the buttermilk. Then, add another ⅓ of the dry ingredients and the rest of the buttermilk. Next, add the rest of the dry ingredients. The whole time mix on low. Scrape bowl. Mix for 15 seconds. Take off mixer.
1 cup Buttermilk
Mix mini chocolate chips and flour together. Add into the batter and gently fold in using a rubber spatula. Pour batter evenly using a kitchen scale between the three pans.
1 cup Mini chocolate chips, ¾ tablespoon All-purpose flour
Bake 20-23 minutes. The cakes are done baking when a toothpick inserted comes out clean. Let cakes sit in the pans for 10 minutes before transferring to a cooling rack. Allow to cool completely.