Preheat your oven to 325°F (163°C). Grease the bottom and sides of a 9-inch springform pan and set aside.

In a mixing bowl, combine the chocolate cookie crumbs, melted butter, and granulated sugar. Mix until well combined and the crumbs resemble wet sand.

Press the mixture firmly into the bottom of the prepared springform pan to create an even crust. Bake the crust in the preheated oven for 10 minutes, then remove and let it cool.

In a separate large mixing bowl, beat the softened cream cheese and granulated sugar with an electric mixer until smooth and creamy.

Add the peanut butter, eggs, vanilla extract, and sour cream to the cream cheese mixture. Mix on low speed until all ingredients are combined and smooth.

Pour the filling over the cooled crust in the springform pan. Spread it evenly.

Bake the cheesecake in the oven for 50-60 minutes, or until the center is set but still slightly jiggly. Turn off the oven, crack the door open, and let the cheesecake cool for about 1 hour.

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

For the ganache, heat the heavy cream in a saucepan over medium heat until just simmering. Remove from heat and add the chocolate chips. Stir until the chocolate is melted and the mixture is smooth.

Once the cheesecake is fully chilled, pour the ganache over the top, spreading it evenly. Top with chopped peanut butter cups and chocolate shavings, if desired.

Return the cheesecake to the refrigerator for at least 30 minutes to allow the ganache to set.

Carefully remove the sides of the springform pan before slicing and serving.