Preheat the oven to 350°F (177°C) and adjust the oven rack to the lower third position. Lightly grease a 9-inch springform pan with nonstick cooking spray.

In a food processor, pulse the Oreo cookies into fine crumbs. In a medium bowl, mix the Oreo crumbs with melted butter and press into the bottom and sides of the springform pan. Wrap aluminum foil around the bottom and sides of the pan.

Bake the crust in the oven for 10 minutes. Allow it to cool slightly while preparing the filling.

In a large bowl, beat the cream cheese and sugar together on medium speed until smooth and creamy (about 3 minutes). Add the sour cream, peanut butter, and vanilla extract, and mix until well combined.

On low speed, add the eggs one at a time, mixing just enough to blend after each addition. Gently fold in three-quarters of the chopped Butterfinger pieces.

Wrap aluminum foil around the springform pan and place it in a large roasting pan. Pour hot water into the roasting pan until it reaches about an inch in height.

Pour the cheesecake batter onto the baked crust and smooth the top. Bake for 50-60 minutes, or until the center is almost set.

Once done, turn off the oven and slightly open the door. Let the cheesecake rest in the oven for 1 hour. Afterward, allow it to cool at room temperature before refrigerating for at least 6 hours or overnight.

Loosen the cheesecake from the rim and remove it. Decorate with the remaining chopped Butterfinger and drizzle with melted peanut butter. Cut into slices and serve chilled.