Red Velvet Cheesecake

To make the Oreo crust: Mist a 9-inch diameter round cake pan with non-stick spray and line with a circle cut from parchment. Place the Oreo cookies in the bowl of a food processor and pulse until finely ground. Drizzle in the melted butter and toss together until combined. Press the mixture into the bottom of the prepared pan. To make the red velvet cheesecake: Preheat the oven to 400 degrees F. Place the cream cheese, sugar, cornstarch, cocoa, and salt in a large mixing bowl, and beat together on medium-low speed until smooth. Scrape the bottom and sides of the bowl with a silicone spatula, then beat in the first egg. Continue adding eggs, one at a time, stopping to scrape the bottom and sides of the bowl after each addition. Stir in the egg yolk, buttermilk, red food coloring, vanilla, and vinegar, and pour the batter over the crust. Place the unbaked cheesecake in a larger dish, and pour water into the larger dish until it comes about halfway up the sides of the pan. Bake for 15 minutes at 400 degrees F, then lower the oven temperature to 300 degrees and bake for an additional 70 minutes, or until the cheesecake is set around the edges but still a little wobbly towards the center. Turn the oven off and leave the cheesecake in to cool down slowly, with the oven door slightly ajar. When the cheesecake has reached room temperature, transfer it to the refrigerator to chill for at least 2 hours (or overnight). Just before serving, flip the cheesecake out of the pan and invert onto a serving plate. Garnish with sweetened whipped cream and chocolate shavings.