Crush the Oreo cookies in a large ziplox bag or using a food processor. Mix in the melted butter.
Press the Oreo mixture firmly into a 8-inch springform / loose-bottom tin. Chill in the refrigerator for 15 minutes.
Cheesecake
Preheat the oven to 160 degrees Celsius.
In a large mixing bowl, beat cream cheese and sugar on medium speed until sugar has been incorporated, about 3 minutes. Beat in the eggs one at a time, incorporating at low speed and scrapping down the sides after each addition. Beat in the vanilla.
With the mixer still on low speed, beat in the sour cream, cocoa powder mixture, corn starch and cooled melted chocolate. Stir in the crushed oreos with a spatula.
Using a fork or skewer, poke holes all over on the bottom of the crust. Pour in the filling and smooth the top with a spatula. Drop the tin several times on the table counter to release large air bubbles.
Bake the cheesecake (I baked mine without the water bath) for 50 minutes to 1 hour. You should be able to see a very slight wobble in the cheesecake.
Place the cheesecake (in the tin) on a wire rack and let cool completely. Refrigerate for at least 4 hours or overnight.
Remove the cheesecake and transfer to a serving platter. For a clean cut, dip the knife into hot water, wipe dry with paper towel, slice, then repeat. Dust with icing sugar and serve.
NOTES
- I used Belcolade 55% chocolate and found the cheesecake still a little sweet. Will use a 70% chocolate in the future! - Recipe adapted from Nigella