Start by preheating your oven to 350°F (175°C). Grease your 9-inch springform pan and line the bottom with parchment paper. This ensures that your cake won’t stick to the pan when it’s done.

In a large bowl, sift together the all-purpose flour, cocoa powder, baking powder, and salt. In a separate bowl, beat the granulated sugar, egg, milk, melted butter, and vanilla extract until smooth. Slowly add the dry ingredients into the wet ingredients, mixing until well combined. Finally, stir in the boiling water (the batter will be thin, but this is perfectly fine).

Pour the cake batter into the prepared springform pan. Bake for about 25-30 minutes, or until a toothpick inserted into the center comes out clean. Let the cake cool in the pan on a cooling rack.

While the cake is cooling, beat the softened cream cheese with the creamy peanut butter in a medium-sized bowl until smooth. Add the powdered sugar and cornstarch, then mix again until fully incorporated. Add the eggs one at a time, beating well after each addition. Finally, fold in the sour cream, creating a smooth, thick batter.

Once the chocolate cake has cooled completely, pour the peanut butter cheesecake batter over the cake layer, spreading it evenly.

Place the springform pan back into the oven and bake the entire dessert at 350°F (175°C) for 45 minutes. The cheesecake should be set around the edges but slightly jiggly in the center. Allow it to cool for 10 minutes in the pan before transferring it to a cooling rack. Let it cool to room temperature, then refrigerate for at least 4 hours (or overnight for best results).

To make the ganache, heat the heavy cream in a small saucepan until it just begins to simmer. Pour the hot cream over the chopped semi-sweet chocolate and let it sit for about 1-2 minutes. Stir until smooth and glossy. Add the butter and powdered sugar, and stir again until fully combined.

Once your cheesecake has chilled, pour the ganache over the cheesecake, spreading it evenly over the top with a spatula. Let the ganache set at room temperature or pop it in the fridge to speed up the process.

Once the ganache is set, slice your Peanut Butter Chocolate Cake Cheesecake into 12 equal pieces. The cake is rich, so smaller slices are perfect!

Serve and enjoy this amazing dessert with friends and family. Don’t forget to snap some photos because this cake is as beautiful as it is delicious!