Step 1: Preheat your oven to 350°F (175°C). This step is crucial for ensuring that your cake layers rise beautifully.
Step 2: Grease the bottom and sides of three 9-inch round cake pans with coconut oil or canola oil. Line the bottoms with parchment paper for easy removal after baking.
Step 3: In a large mixing bowl, whisk together all-purpose flour, granulated sugar, cocoa powder, baking powder, baking soda, and salt until well combined.
Step 4: In another bowl, mix whole milk, full-fat sour cream, liquified coconut oil (or canola oil), eggs, egg yolks, and vanilla extract. Whisk until smooth.
Step 5: Slowly pour the wet mixture into the dry ingredients while mixing on low speed. Carefully add hot water to the batter, mixing until smooth. The batter will be quite liquid, and that's normal!
Step 6: Gently fold in crushed Oreo cookies into the batter, ensuring they are evenly distributed.
Step 7: Divide the batter evenly among the prepared pans. Bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean. Allow the cakes to cool in the pans for 10 minutes before transferring to a wire rack to cool completely.
Step 8: In a large bowl, beat together unsalted butter until creamy. Gradually add confectioners' sugar and cocoa powder. Mix until combined. Slowly add half-and-half, salt, and vanilla extract. Beat until the frosting is light and fluffy.
Step 9: Once the cakes are completely cool, place one layer on a serving plate. Spread a generous amount of frosting on top, then sprinkle with crushed Oreo cookie crumbs. Repeat this process with the second layer. Top with the final layer of cake and frost the top and sides of the entire cake.
Step 10: For a finishing touch, decorate the top of the cake with remaining crushed Oreo crumbs and whole Oreos if desired. Slice, serve, and enjoy!
