Four layers of rich, sensational, chocolate love. Oreo crumb crust. Velvety chocolate cheesecake. Intense chocolate ganache. Fluffy chocolate whipped cream. This cheesecake is not for the faint of heart.
Heat oven to 350°. In a small microwave safe bowl melt 1 cup chocolate chips on half power until melted (or use a double boiler). Set aside to cool. Spray a 10" springform with cooking spray and wrap the bottom with tin foil.
In a food processor grind 25 Oreos into fine crumbs. Dump into a medium mixing bowl and mix in the melted butter until completely combined. Press into the bottom of the springform and bake for 8 minutes. Set aside to cool while you make the cheesecake layer.
In the bowl of a stand mixer with the paddle attachment whip the cream cheese until all the lumps are gone. You may have to scrape the bowl several times. Add the sugar and whip until light and fluffy, scraping down the bowl as you go. Mix in the cornstarch and cocoa, scrape the bowl. Add one egg at a time, scraping after each addition. Mix in the sour cream, vanilla and salt until well combined. While the machine is running slowly pour in the melted chocolate until completely incorporated.
Using the kettle boil some water. Place the springform inside the roasting pan and fill with the cheesecake batter. Pour the boiling water into the roasting pan so it comes half an inch up the side of the springform. Check out my Cheesecake Tips post on some helpful water bath tips.
Bake the cheesecake for 50-60 minutes. The edges will be puffy but the center will still look jiggly. Shut the oven off, leaving the cheesecake inside to set. Prop the oven door open with a wooden spoon and let rest for one hour. Place on the counter until it has come to room temperature, then refrigerate for several hours or overnight.
After the cheesecake has had at least an hour in the fridge the ganache can be made. Melt the 1.25 cups chocolate chips and 1 cup heavy cream in a small microwave safe bowl at half power (or in the top of a double boiler). Whisk often and once completely melted and combined let cool for 20 minutes. Leaving the springform pan intact, pour the ganache over the cheesecake and allow to set in the refrigerator for the remaining time.
To make the whipped cream, pour the whipping cream into the bowl of a stand mixer with the whisk attachment. Whip into soft peaks. Sift in the cocoa and icing sugar. Add the vanilla and salt and whip into firm peaks.
Run a knife along the side of the springform pan and then carefully remove the wall. Fill the piping bag with the chocolate whipped cream and apply decoratively. Now you are ready to serve and enjoy!