Steps to Make the Cake

• Preheat your oven to 350°F (176°C) and prepare three 8-inch cake pans by greasing them and lining the bottoms with parchment paper for easy release.
• In a large mixing bowl, cream together the unsalted butter, sugar, and brown sugar with peanut butter until light and fluffy. Then, add in the sour cream and vanilla extract, mixing well before incorporating the eggs one by one.
• In a separate bowl, whisk together the all-purpose flour, baking powder, and salt. Gradually mix half of this dry mixture into your wet batter before adding the milk and water. Finally, fold in the remaining dry ingredients until smooth and combined.
• Evenly divide the batter among the prepared pans and bake for 21-23 minutes, or until a toothpick inserted into the center comes out with just a few moist crumbs. Allow the cakes to cool in the pans for 2-3 minutes before transferring them to a wire rack.
• In another bowl, beat together the salted butter and peanut butter until creamy. Gradually add powdered sugar, mixing until smooth, and adjust the consistency with a little water or milk if needed.
• Once the cakes are completely cool, level them off with a knife if necessary. Layer the cakes with frosting in between each layer and cover the whole cake with the remaining frosting. For a delightful finish, press peanut butter chips into the sides and drizzle the top with rich ganache.