Preheat oven to 375F

Grease (4) 9-inch cake pans. Set to the side.

Make the brownie batter by following the instructions and ingredients on the box. Be sure to make 2 boxes.

Pour the brownie batter into 2 of the greased cake pans. 

Remove the packages of the cookie dough and place in the greased cake pans. One package for each pan.

Press the cookie dough evenly into the pan.

Place all 4 cake pans into the oven for 2-25 minutes. (I usually add the brownie pans to the top rack and cookie pans on the bottom rack.)

Remove from the oven and place on a wire rack to cool completely.

Pour the heavy whipping cream into a medium microwave safe bowl and heat in the microwave for 1 minute. Make sure to keep an eye on it so it doesn't bubble over.

Transfer the chocolate chips to a large mixing bowl and pour the warm heavy whipping cream over the chocolate and let it sit for 2-3 minutes. Start whisking slowly in the middle of the bowl, and continue whisking in one direction until the mixture is smooth and well combined.

Allow to cool for about 10 minutes.

In a stand mixer, add the butter and the vegetable shortening. Beat together on medium speed until combined and fluffy.

Slowly add the vanilla extract, milk along with the powdered sugar.

Add the peanut butter and beat together for 40 seconds or until fluffy and stiff.

Place one cake layer on a cake stand. Carefully spread an even layer of peanut butter buttercream over the top followed by chocolate ganache. 

Repeat this process for each all 3 layers.

Decorate the outside of the cake as desired. I used a 2110 tip and just did quick half circles around the entire cake.

Top the cake with crushed chocolate chip cookies and drizzle with more ganache if desired.