Ingredients
Equipment
Method
- Preheat your oven to 350ºF (177ºC). Spray three 6-inch or two 8-inch cake pans with cooking spray and line the bottoms with wax or parchment paper circles.
- Add all dry cake ingredients (flour, sugar, cocoa, baking soda, baking powder, salt) to the bowl of a stand mixer. Mix on low for 30 seconds to combine.
- Add the oil, eggs, vanilla, and buttermilk to the dry ingredients. Mix on low just until everything is combined.
- With the mixer running on low, slowly pour in the hot coffee or water. Once added, increase the speed to medium and beat the batter until smooth, about 2 minutes.
- Divide the batter among prepared pans, filling each no more than two-thirds full. Bake for 32–36 minutes, or until a toothpick inserted in the center comes out clean. Let cakes cool fully in the pans.
- To make the buttercream, pulse 13 Oreo cookies in a food processor until very finely ground.
- In a stand mixer fitted with the paddle attachment (or in a large bowl with a hand mixer), beat the butter on medium-high until pale and creamy, about 5 minutes.
- Add powdered sugar a few cups at a time, mixing on low and scraping the bowl between additions. Once all sugar is added, mix in vanilla, milk, and salt on low speed until smooth and fully combined, 1–2 minutes.
- On low speed, blend in the finely ground Oreo crumbs until evenly distributed throughout the buttercream.
- Once the cake layers are completely cool, trim them to your preferred height. Swipe a bit of buttercream on a cake board or plate, and set the first cake layer on top.
- Spread cookies & cream buttercream between each cake layer, stacking as you go. Cover the entire cake with a thin crumb coat of frosting.
- Place the cake in the fridge for 15–20 minutes, allowing the crumb coat to set.
- After chilling, apply the remaining buttercream smoothly over the cake.
- Set aside 8 whole Oreos for the top. Chop the remaining 4 Oreos (from the garnish section) into various sizes.
- Decorate the base of the cake by pressing the chopped Oreo pieces around the bottom third in a mosaic pattern. Arrange the whole Oreos decoratively on top, if desired.
Notes
For the deepest Oreo flavor, use black cocoa powder, though Dutch-processed cocoa works in a pinch with a lighter result. Buttercream consistency can be adjusted with extra milk or chilling briefly if needed. Make sure the cake layers are completely cool before frosting to prevent sliding or melting. Cake layers and buttercream can be made ahead—store cake tightly wrapped at room temperature and buttercream in the fridge, bringing to room temp and rewhipping before use. Leftover cake stays fresh covered at room temperature for up to two days or refrigerated for up to five days; let it sit at room temp before serving for best texture. Individual slices and unfrosted cake layers both freeze well.