Preheat the oven to 325°F (163°C). Grease a 9-inch springform pan and set it aside.
In a medium bowl, combine graham cracker crumbs, melted butter, and sugar. Press this mixture firmly into the bottom of the springform pan to form an even crust.
In a large mixing bowl, beat cream cheese and peanut butter on medium speed until smooth and creamy.
Gradually add granulated sugar and continue beating until fully incorporated.
Add eggs one at a time, beating well after each addition.
Stir in vanilla extract and sour cream until the mixture is smooth.
Pour the filling over the crust in the pan, smoothing the top with a spatula.
Bake for 50-60 minutes, or until the edges are set and the center is slightly jiggly.
Turn off the oven and leave the cheesecake inside for an additional hour.
Remove the cheesecake from the oven and allow it to cool to room temperature.
Refrigerate for at least 4 hours or overnight for best results.
To prepare the topping, whip the heavy cream until soft peaks form.
In a separate bowl, mix peanut butter and powdered sugar until smooth.
Gently fold the peanut butter mixture into the whipped cream until combined.
Spread the peanut butter topping evenly over the chilled cheesecake just before serving.