Lightly grease the bottom and sides of a 9″ or 10″ springform pan. Set aside. Meanwhile, mix the 1 Tablespoon milk and the black coffee into a small bowl; set aside.

In the bowl of a stand mixer, whip the heavy whipping cream and confectioners’ sugar together with the whisk attachment on HIGH speed for about 5-7 minutes or until stiff peaks form. Spoon the whipped cream into a medium bowl and set aside.

In the same bowl for the stand mixer, cream together the cream cheese, granulated sugar and vanilla extract with the paddle attachment until soft and creamy, about 2 minutes. Fold the whipped cream mixture into the cream cheese mixture with a rubber spatula until no streaks of whipped cream remain and mixture is fully incorporated.

Spread a little bit of the cream cheese mixture into the bottom of the springform pan to help adhere the first Oreo layer. Dunk each Oreo, one at a time, into the coffee mixture and layer around the bottom of the pan, breaking Oreo pieces if necessary to fit. Spread 1/3 of the cream cheese mousse mixture evenly over the first Oreo layer; grate some of the chocolate from the chocolate bar over the cream cheese mousse layer. Repeat with Oreo layer, then cream cheese mousse, then grated chocolate layers. Repeat once more for a total of three layers.

Cover and refrigerate for at least 4-6 hours, or up to overnight, to allow cake to set and flavors to meld. Just before serving, garnish with additional whipped cream and chocolate curls, if desired.