Preheat the oven to 180°C / 350°F / Gas mark 4.
Spray a 22cm spring form tin with cooking spray and set aside.
Using a food processor, pulse the whole Oreos into fine crumbs.
In a medium sized bowl, stir the cookie crumbs and melted butter together.
Press into the bottom slightly up the sides of the prepared tin. Note: The crust should be thick.
Line foil on the bottom and tightly around the outside walls of the spring form tin
Bake the crust for 7-8 minutes. Allow to cool slightly.
Using a handheld mixer fitted with a paddle attachment or a food processor, beat the cream cheese and granulated sugar together until the mixture is smooth and creamy.
Add the sour cream, peanut butter, and vanilla and blitz/beat until combined.
Add the eggs one at a time, beating after each until just blended. Do not over mix the filling after you have added the eggs.
Using a rubber spatula or large wooden spoon, fold in ¾ of your chopped KitKats.
Pour the filling into the cooled crust.
Place the spring form tin into a large roasting pan and place into the oven.
Fill with about 2.5cm of hot water. The foil wrapped around the tin will prevent water from leaking inside.
Bake for 50-60 minutes or until the centre 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 it to cool completely at room temperature.
Refrigerate for at least 6 hours or overnight (preferred).
Loosen the cake from the rim of the pan and remove the rim.
Top with additional chopped KitKats and peanuts if using.
Cut into slices and serve chilled.