This three tiered 6 inch cake recipe is a perfect representation of an Oreo cake! It features moist black cocoa cake layers and an Oreo loaded buttercream frosting.
Preheat oven to 350°F. Place the oven rack in the middle of the oven. Using nonstick cooking spray that contains flour, generously spray 3 -- 6 inch cake pans. Set aside.
In the bowl of a stand mixer whisk the cake flour, sugar, cocoa powder, baking soda, and salt.
In a separate bowl, or large liquid measuring cup, whisk the vegetable oil, sour cream, buttermilk, egg, vanilla extract, white vinegar, and black food coloring. Add the wet ingredients to the dry ingredients (using a paddle attachment) and mix on low until ingredients are combined.
Pour the batter into the three cake pans, use an off set spatula to spread the batter into an even layer. Tip: use a kitchen scale to ensure equal amounts of batter in each pan.
Place the cake pans in the oven and bake for 25-28 minutes. The cake is done when a toothpick inserted in the center comes out clean or with a few moist crumbs. (The cake will be more moist if you don't over bake it, so I like to remove it when the toothpick has moist crumbs on it-- but no wet batter). Remove from the oven and let the cakes cool in the pan for 10 minutes before turning out onto a wire rack to cool completely.
Oreo Frosting
While the cake layers are cooling make the Oreo frosting. In the bowl of a stand mixer fitted with a paddle attachment cream the butter until smooth, about 2 minutes on medium speed.
Add the powdered sugar and heavy cream and whip until smooth. Add the vanilla extract, crushed Oreos, and salt. Mix on medium speed until light and fluffy. About 3-4 minutes. Add more heavy cream, a tablespoon at a time, if needed, to reach your desired consistency.
Assembly
Place a cake layer on a cake stand or cake plate, place a very large dollop of Oreo frosting on top of the cake layer and using an offset spatula, spread the frosting until it covers the top of the cake. Place another cake layer on top of the frosting. Add Oreo frosting to the top of the cake and spread until it's in a thick even layer. Place the last cake layer on top and then use the remaining frosting to cover the top and sides of the cake. Tip: If piping this frosting use a tip that has a bigger diameter, sometimes the crushed Oreo cookies can clog up smaller piping tips.