Preheat the oven to 350°F (175°C). Grease and flour three 8-inch round cake pans.
In a medium bowl, whisk together the flour, cocoa powder, baking soda, and salt.
In a large bowl, beat the butter, granulated sugar, and brown sugar until creamy and fluffy. Add the eggs one at a time, beating well after each addition. Stir in the vanilla extract.
Alternately add the flour mixture and buttermilk to the butter mixture, beginning and ending with the flour mixture. Mix just until combined.
Stir in the hot water until the batter is smooth. Pour the batter evenly into the prepared cake pans.
Bake for 30-35 minutes or until a toothpick inserted into the center comes out clean. Cool in the pans for 10 minutes, then remove to wire racks to cool completely.
For the peanut butter filling, beat the peanut butter, powdered sugar, and heavy cream together until smooth and fluffy.
Assemble the cake by placing one layer on a serving plate, spreading with peanut butter filling. Repeat with remaining layers.
For the chocolate ganache, melt the chocolate chips and heavy cream together until smooth. Pour over the top of the cake.
Garnish with peanut butter chips and chopped peanuts.
Prep Time: 25 minutes | Cooking Time: 35 minutes | Total Time: 1 hour | Kcal: 500 kcal per serving | Servings: 12 servings.
