Combine the crust ingredients until thoroughly combined.
Press onto the bottom and partially up the sides of a lightly greased 10-inch springform pan. Set aside.
To make the filling:
Preheat oven to 350°F (175°C).
Beat together the cream cheese, brown sugar, cornstarch, and sour cream until smooth. Add the eggs one at a time, mixing well after each. Mix in the vanilla extract and peanut butter. Mix in the melted chocolate, followed by the peanuts. Pour the filling over the crust. (I recommend setting the pan on a lined rimmed baking sheet to catch any potential spills or leaks.)
Bake for 15 minutes.
Reduce oven temperature to 200°F (95°C), and bake for 2 hours to 2 hours 10 minutes, or until the center is set and doesn't look wet. Remove the cheesecake from the oven, and run a knife around the edges to loosen it from the pan.
Return the cheesecake to the oven, turn the oven off, and leave the cheesecake in the oven for 2 hours.
Refrigerate overnight.
To make the topping:
Melt the white chocolate and peanut butter in a saucepan over low heat. (Or at half-power in the microwave in 30-second increments until melted) Cool to lukewarm.
Spread the cooled topping over the chilled cheesecake.
Drizzle the melted chocolate over the topping. Use the dull side of a knife to create a swirl design. Chill until the topping sets.
Notes
Recipe slightly adapted from I Love Cheesecake.
Store this chocolate peanut butter cheesecake in the refrigerator tightly wrapped (or in an airtight container) for up to 5 days.