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

In a food processor or blender, pulse the whole Oreos (cream filling and cookie) into a fine crumb. You should have about 2 cups (packed) crumbs, or 250g. Combine the Oreo crumbs and melted butter together in a medium bowl. Press tightly into the bottom and up the sides of prepared pan. Wrap aluminum foil on the bottom and tightly around the outside walls of the springform pan. This helps prevent leakage.

Bake crust for 10 minutes. Allow to slightly cool as you prepare the filling. Leave oven on.

Using a handheld or stand mixer fitted with a paddle attachment, beat the cream cheese and granulated sugar together on medium speed in a large bowl—about 3 full minutes until the mixture is smooth and creamy. Add the sour cream, peanut butter, and vanilla, beat until combined. On low speed, add the eggs one at a time, beating after each addition until just blended. Do not overmix the filling after you have added the eggs. Using a rubber spatula or large wooden spoon, fold in 3/4 of your chopped Butterfingers. The rest will be for decorating the top of the finished cheesecake.

If needed for extra visuals, see my How to Make a Cheesecake Water Bath; the visual guide will assist you in this step. Boil a pot of water. You need 1 inch of water in your roasting pan for the water bath, so make sure you boil enough. I use an entire kettle of hot water. As the water is heating up, wrap the aluminum foil around the springform pan. Place the pan inside of a large roasting pan. Pour the cheesecake batter on top of the crust. Use a rubber spatula or spoon to smooth it into an even layer. Carefully pour the hot water inside of the pan and place in the oven. (Or you can place the roasting pan in the oven first, then pour the hot water in. Whichever is easier for you.)

Bake for 50-60 minutes or until the center is almost set.* Turn the oven off and open the door slightly. Let the cheesecake sit in the oven for 1 hour. Remove from the oven and allow to cool completely at room temperature. Refrigerate for at least 6 hours or overnight (preferred).

Loosen the cheesecake from the rim of the pan and remove the rim. Top with additional chopped Butterfingers and drizzle with melted peanut butter. Cut into slices and serve chilled.Cover leftover cheesecake and store in the refrigerator for up to 4 days.