Preheat oven to 350 degrees and spray cake pans with non stick baking spray. Set aside
In a large bowl, combine cake mix, eggs, butter, and milk until smooth.
Divide the cake mix between (3) 9 inch round cake pans. Bake in the oven for 30-35 minutes or until a toothpick inserted in the center comes out clean.
For the Oreo Frosting
In a large bowl, beat butter and vanilla until light and fluffy. Add powdered sugar a little at a time. Add heavy cream as needed to reach out desired consistency. Fold in crushed oreos.
Scoop 1 cup of frosting into a piping bag and set aside
Chocolate Ganache Directions
Pour the heavy whipping cream into a small saucepan. Heat over medium heat. Pour the chocolate chips into a medium heat safe bowl
Once the heavy whipping cream starts to simmer, remove from heat and pour onto the chocolate chips. Allow to sit for 1 minute before whisking until smooth. Pour into a squeeze bottle.
Building the Cake
Once the cakes are cooled, remove them from the pans. Using the cake leveler, cut the domes off the tops of the cakes to even them out
Place one cake round onto the cake board.Scoop 1 cup of frosting onto the top of the cake round and spread evenly with an offset spatula. Repeat with remaining layers.
Spread top and sides of cake with remaining frosting. Refrigerate for at least 1 hour.
Decorating the Cake
Remove cake from fridge and drip ganache all around the edge of the cake.
Pipe dollops of frosting onto the top of the cake using a star tip . Place whole oreos onto the sides of the dollops
Ingredient Notes and Shopping Tips
Triple Chocolate Cake Mix: I like Duncan Hines.
Whole Milk: Using milk instead of water for a moist cake with a tender crumb.
Butter: Use unsalted butter here so you don't end up with an overly salty buttercream. You can always add a pinch of salt at the end if you feel it's needed.
Tips For Success
Don't overbake: Overbaking will lead to a dry cake. Bake just until a toothpick inserted in the center comes out clean, or with just a few crumbs. If your toothpick contains wet batter keep baking a few minutes at a time.
Flat Layers: You can use cake strips to help bake flat layer cakes. However, I prefer to use a cake leveler after baking. (Bonus: You can snack on it while building your cake).
Oreo Frosting: Crush cookies finely using a plastic baggie with a rolling pin, or a meat mallet. You can also use a food processor if you have one (I don't!). If the Oreos are too chunky they will clog your piping tip.
Round Cake Boards: These make it easy to move your cake from counter to table. It also makes transport more stable if you want to take it to a birthday party. If you don't like these you can also use a cutting board instead.
Smooth Frosting: Get smooth frosting every time with an Angled Spatula.
Use a Squeeze Bottle: to drip ganache down the sides of the cake.