Preparation Steps

• Preheat the oven to 350°F (175°C). Grease and flour two 8- or 9-inch round cake pans and line the bottoms with parchment paper.
• In a medium bowl, whisk together the all-purpose flour, baking powder, baking soda, and salt. Set aside.
• In a large bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy, about 3 to 4 minutes.
• Beat in the creamy peanut butter until fully incorporated and smooth.
• Add the eggs one at a time, beating well after each addition, then stir in the vanilla extract.
• Alternately add the dry ingredients and the milk to the peanut butter mixture, beginning and ending with the dry ingredients. Mix until just combined; do not overmix.
• Divide the batter evenly between the prepared pans and smooth the tops. Bake in the preheated oven for 25 to 30 minutes, or until a toothpick inserted into the center comes out clean.
• Allow the cakes to cool in the pans for 10 minutes, then turn out onto a wire rack to cool completely before frosting.
• To make the frosting, beat the softened butter and peanut butter together until smooth. Gradually add the powdered sugar, beating on low until incorporated, then add the heavy cream and vanilla and beat until light and fluffy. Adjust consistency with more cream or powdered sugar as needed.
• Assemble the cake: place one cake layer on a serving plate, spread a layer of frosting, top with the second layer, and frost the top and sides. Smooth the frosting or create swirls as desired.
• Slice and serve. Store covered at room temperature for up to 2 days or refrigerate up to 5 days.