Preheat the oven to 350°F.

In a food processor, pulse the Oreos into fine crumbs. Mix with the melted butter and sugar, then firmly press the mixture into the bottom and about 1 inch up the sides of an 8-inch springform pan.

In a large bowl, beat the cream cheese and sugar until smooth and fluffy. Add the eggs, vanilla, sour cream, and flour, mixing just until combined.

Pour half of the cheesecake batter into the prepared crust.

Microwave half of the hot fudge sauce for about 30 seconds, or until pourable. Pour it evenly over the batter, then sprinkle with 3 chopped Butterfinger bars and 3 chopped peanut butter cups.

Top with the remaining cheesecake batter and smooth the surface.

Bake for 50–60 minutes, until the edges are set and the center still has a slight jiggle. Cool completely at room temperature, then refrigerate for at least 4 hours, or overnight.

Before serving, warm the remaining hot fudge and spread it over the cheesecake. Top with the remaining chopped Butterfinger bars and peanut butter cups.

For the frosting, beat together the peanut butter, 4 ounces of cream cheese, and butter until smooth. Add the powdered sugar and beat until creamy.

Transfer the frosting to a piping bag (or a zip-top bag with the corner snipped off) and pipe dollops around the edge of the cheesecake. Slice and serve.