Preheat oven to 350º Fahrenheit. Grease and flour 2 round 9-inch cake pans.
For the cake, put flour, sugar, cocoa, baking powder, baking soda and salt in a bowl. Use a whisk to whisk the ingredients well.
In a stand mixer, mix the buttermilk, oil, eggs, vanilla together.
Slowly add in the mix of dry ingredients while the mixer is on low.
Add the coffee and make sure everything is combined. The batter will be very thin.
Pour the batter into the prepared pans and bake for about 25 minutes or until a toothpick inserted in the middle comes out clean.
Turn the cakes out onto a cooling rack. While the cakes are cooling, make your frostings.
Peanut Butter Frosting:
In the bowl of a stand mixer, cream together butter and peanut butter for 2 minutes.
Add 1 cup of powdered sugar and mix until blended.
Add 2 tablespoons of heavy cream and beat until completely blended.
Add in the remaining cup of powdered sugar. Beat for 1 minute.
Test the frosting and if you need another tablespoon or two of heavy cream to make the frosting spreadable, add it in.
Make the Chocolate Buttercream.
In a stand mixer with the beater blade, beat the butter for 1-2 minutes until it is smooth, creamy and nearly white in appearance.
Add in the salt and vanilla. Mix until incorporated.
With the mixer on low speed, slowly add in the powdered sugar and cocoa powder.
Add the heavy cream, a tablespoon at a time, mixing slowly until it is the consistency that you'd like.
Beat for 1 minute on medium speed until smooth and creamy.
Assemble the Cake:
Place one cake layer on a plate.
Frost the top of the first cake with the Peanut Butter Frosting. Then layer the other half of the cake on top. Frost the outside of the cake with the Chocolate Buttercream Frosting.
Pipe flowers on top with the leftover Peanut Butter Frosting and/or decorate as desired with chopped Reese's Peanut Butter Cups.
Store in an airtight container at room temperature.
The calories shown are based on the cake being cut into 15 pieces, with 1 serving being 1 slice of cake. Since different brands of ingredients have different nutritional information, the calories shown are just an estimate. **We are not dietitians and recommend you seek a nutritionist for exact nutritional information. The information in the nutrition box are calculated through a program and there is room for error. If you need an accurate count, I recommend running the ingredients through your favorite nutrition calculator.**Originally published on April 20, 2013.