Preheat the oven to 350°F. Prepare three 8-inch or four 6-inch cake pans by spraying the sides with a cooking spray and a parchment paper circle fitted to the bottom of the pan. Alternatively, you can grease and lightly flour the pans.

Sift the cake flour and then measure by spooning and leveling it in your measuring cup. Add the cake flour, baking powder, baking soda, and salt into a bowl and whisk to combine. Set aside.

In the bowl of your stand mixer, cream the butter for on high for two minutes until it's light and fluffy. Add in white and brown sugars and continue to mix on medium-high for another two minutes, scraping down the bowl and paddle as needed. Turn the mixer to low and add the eggs one at a time. Add the vanilla and sour cream, turn the mixer to high, and mix for one minute, scraping down the bowl and paddle once more.

With the mixer on low speed, add in the dry ingredients and mix until just combined. Add the whole milk and mix until just incorporated. Scrape down the sides and bottom of the bowl and give it a few stirs to make sure there are no lumps, then fold in the flour-coated chocolate chips (optional). Batter will be slightly thick, but pourable.

Pour batter evenly into prepared cake pans (about ⅔ of the way full) and bake for 35-40 minutes. The cakes are done when they spring back to the touch and a toothpick inserted into the middle comes out clean. Let the cakes cool in the pan for five minutes before turning them out onto a wire rack for an additional few hours of cooling. Make sure they're entirely room temperature before applying any frosting.

With a hand mixer or paddle attachment on your stand mixer, cream the butter on medium-high until it’s creamy and light (almost white) in color. About 7 minutes.

Add the powdered sugar, one cup at a time, scraping down after each addition and making sure each cup is fully incorporated before adding the next one. Add vanilla, milk, and salt and mix on medium-low for another two minutes until fully incorporated.

Fill about 1 cup frosting in each layer. Can mix in crushed Oreos to the filling frosting. Crumb-coat entire outside of cake and let set. Frost the cake with vanilla buttercream. Crumble the chocolate chip cookies and garnish the cake by adding them to the bottom third of the frosted cake, pressing the crumbles in to the sides.

If garnishing with a chocolate ganache drip, chill the cake for 30 minutes before dripping with ganache. Finish by piping a border on top with vanilla buttercream (I used Wilton Tip 1M) and placing whole chocolate chip cookies on top.