How to Make It
MAKE THE CRUST Preheat the oven to 350°. In a food processor, pulse the chocolate wafers with the salt until the cookies are finely ground. Transfer to a small bowl and stir in the butter. Press the crumbs evenly over the bottom and halfway up the side of a 9-inch springform pan. Bake for about 10 minutes, until the crust is set. Let cool on a rack. Wrap the springform pan tightly in aluminum foil.
MAKE THE CHEESECAKE FILLING Reduce the oven temperature to 300°. In a stand mixer fitted with the paddle, beat the cream cheese at low speed with the sugar until smooth, about 3 minutes. Beat in the eggs, 1 at a time, scraping down the bowl between additions. Add the vanilla and kosher salt. Slowly beat in the cream until no streaks remain.
Transfer 1 cup of the cheesecake filling to a small bowl. Add the cocoa powder and red food coloring to the remaining filling and beat on low speed, scraping the side of the bowl as needed, until no streaks remain.
Pour the red cheesecake filling into the pan. Spoon heaping tablespoons of the reserved white filling over the red filling and use a wooden skewer to swirl.
Set the cheesecake in a medium roasting pan, and carefully fill the roasting pan with enough hot water to reach halfway up the sides of the pan. Bake for 1 hour and 45 minutes, until set around the edges and slightly jiggly in the center. Turn off the oven, and let the cheesecake rest for 40 minutes longer.
Remove the cheesecake from the roasting pan and transfer to a rack. Carefully remove the foil and let the cheesecake cool to room temperature, about 1 hour. Run a sharp, thin-bladed knife around the cake and refrigerate until chilled and firm, at least 1 hour. Remove the ring and serve.