• You will need two 9 inch round brownie layers and two 9 inch round cake layers. If you have enough pans, feel free to make them both at once, but I had to do them separately since I only have two 9 inch pans.
• Grease the pans then cut 2 circles of parchment paper the same diameter of the pan and place them in the bottom. Grease the top of the parchment paper.
• Prepare the brownie mix according to package directions. Divide the batter evenly between the two pans. Bake according to package directions. Allow to cool in the pans, then run a knife along the outside edge. Flip the pans and the brownie should come right off. Peel off the parchment paper.
• Repeat with the cake batter.
• Meanwhile, make the frosting. In the bowl of an electric mixer, beat together peanut butter, cream cheese, butter, and vanilla. Add in the powdered sugar, a few cups at a time, beating slowly after each addition (otherwise you'll end up with huge mushroom clouds of powdered sugar!). Once most of the powdered sugar is incorporated, add in 4 Tablespoons of the half and half. Beat on high speed until smooth. The frosting should be thick but easily spreadable. If it still pulls when you try to spread it with a knife, add more half and half, a Tablespoon at a time, until the desired consistency is reached.

To assemble:

• Once the cakes and brownies are all cooled and removed from the pans, you're ready to start frosting! Start by putting a small dollop of frosting on the plate/board/platter where you'll be frosting the cake. (Note: Only do this if you aren't intending to move the cake after decorating it.) Place one layer of brownie on top. Add a large scoop of frosting and use an offset spatula to work the frosting from the center out to the outsides of the cake. It's fine if there's frosting hanging off the sides.
• Place a layer of cake on top of the first layer of frosting. Follow the same frosting techniques. Repeat with the remaining layer of brownie and cake.
• For the final layer, place a large scoop of frosting on top of the cake and use a spatula to press it out to the edges. You want this layer to be fairly thin. It's main purpose is to pick up any loose crumbs. Use your spatula to smooth out the extra frosting on the sides. Refrigerate the cake for at least an hour.
• In the meantime, make the ganache. Chop the chocolate and place it in a heat proof bowl. Heat the cream in a saucepan over medium heat until very hot to the touch. Pour it over the chopped chocolate and allow it to set for a few minutes. Stir the mixture vigorously until it begins to form a smooth, creamy chocolate coating.
• Once the crumb coat is set, remove the cake from the fridge and give it one last coat of frosting. Pour the ganache over top of the cake, allowing it to drip over the sides. Decorate with peanut butter chips, if possible.