Preheat the oven to 325°F (163°C).

In a mixing bowl, combine chocolate graham cracker crumbs, melted butter, and granulated sugar until well mixed. Press this mixture firmly into the bottom of the 9-inch springform pan to form the crust. Bake for 10 minutes, then remove from the oven and cool.

In a large mixing bowl, beat the softened cream cheese and sugar together until smooth and fluffy. Add in the peanut butter and mix until well combined.

Incorporate the eggs one at a time, mixing well after each addition. Add vanilla extract, sour cream, and heavy cream, mixing until the filling is creamy and smooth.

Pour the cheesecake filling over the cooled crust and spread evenly.

Bake in the preheated oven for 50-60 minutes, or until the center is set but slightly jiggly. Turn off the oven and leave the cheesecake inside for an additional hour.

Remove the cheesecake from the oven and allow it to cool to room temperature. Once cooled, refrigerate for at least 4 hours or overnight for best results.

To prepare the chocolate ganache, heat the heavy cream in a small saucepan until simmering. Pour over the chocolate chips in a mixing bowl and let sit for a few minutes. Stir until smooth.

Once the cheesecake is chilled, pour the chocolate ganache over the top and spread evenly. Top with chopped peanut butter cups and drizzle with additional chocolate if desired.

Slice and serve chilled.