Preheat the oven to 350℉. Spray three 8-inch cake pans with baking nonstick spray. Line the bottoms with parchment paper and spray again. Set aside.
In a medium bowl, sift the flour, cocoa powder, baking powder, baking soda, and salt. Set aside.
3 1/2 cups All-purpose flour, 1/4 cup Unsweetened cocoa powder, 2 tsp Baking powder, 1/2 tsp Baking soda, 1 tsp Salt
Using a mixer with a large bowl, beat the butter, oil, and sugar on high speed for 2 minutes. It will become very pale in color and fluffy.
1/2 cup Oil, 1/2 cup Unsalted butter, 1 3/4 cup White granulated sugar
Add in the vanilla, vinegar, sour cream, eggs, and red food dye. Mix on medium until combined.
1 tsp Pure vanilla extract, 1 tsp White vinegar, 1/3 cup Sour cream, 4 Large eggs, 1 tsp Red food gel dye
Add in the dry ingredients and buttermilk. Mix on low until just combined. Take off the mixer and stir using a baking rubber spatula. Add in the mini chocolate chips and fold them in.
1 cup Buttermilk, 1 1/2 cups Mini chocolate chips
Divide the batter evenly between the three pans and smooth evenly. Bake for 25-30 minutes. Bake until a toothpick inserted comes out clean.
Let the cakes sit in the hot pans for 10 minutes before transferring to a cooling rack. Cool completely before decorating.