Preheat your oven to 325°F (165°C). Grease and flour two 9-inch round cake pans.

In a medium bowl, whisk together the flour, cocoa powder, baking powder, baking soda, and salt. Set aside.

In a large mixing bowl, beat the softened butter and granulated sugar until light and fluffy, about 3–4 minutes. Add the eggs one at a time, beating well after each addition, and stir in the vanilla extract.

Gradually add the dry ingredients to the butter mixture, alternating with buttermilk, beginning and ending with the dry ingredients. Mix until just combined.

Divide the batter evenly between the two prepared cake pans.

In another large bowl, beat the cream cheese until smooth. Add granulated sugar and beat until creamy. Add the eggs one at a time, beating well after each. Stir in vanilla extract and peanut butter until combined.

Spoon the peanut butter cheesecake mixture evenly over the chocolate cake batter in each pan.

Bake in the preheated oven for 50–60 minutes, or until the cheesecake layer is set and a toothpick inserted into the center comes out clean.

Let the cakes cool in the pans for 15 minutes, then run a knife around the edges and remove from the pans. Transfer to a wire rack to cool completely.

In a large mixing bowl, beat the softened butter and peanut butter until creamy. Gradually add powdered sugar, alternating with heavy cream, beating until smooth. Stir in vanilla extract.

Once cooled, place one cake layer on a serving plate, cheesecake side up. Spread a layer of frosting over the top. Place the second cake layer on top, cheesecake side down.

Frost the top and sides of the cake with remaining peanut butter frosting. Slice and enjoy.