Preheat your oven to 325°F (163°C). In a mixing bowl, combine crushed Oreos with melted unsalted butter until the mixture resembles wet sand. Firmly press this mixture into the bottom of a 9-inch springform pan to form an even layer. Bake the crust in the preheated oven for 11 minutes, then remove and let it cool while you prepare the filling.

In a large mixing bowl, beat together room-temperature cream cheese and granulated sugar until the mixture is smooth and creamy, about 2-3 minutes. Gradually add in the hot cocoa mix, unsweetened cocoa powder, sour cream, heavy cream, and pure vanilla extract. Mix until well combined and creamy, ensuring there are no lumps for your hot chocolate cheesecake.

With the mixer on low speed, add the eggs one at a time to the cream cheese mixture, mixing just until incorporated after each addition. This gentle mixing helps maintain the cheesecake's structure. After all the eggs are fully combined, scrape down the sides of the bowl to ensure everything is mixed evenly and smooth.

Pour the creamy filling over the cooled Oreo crust, spreading it evenly. To prevent cracks, place the springform pan in a larger roasting pan and fill the outer pan with hot water halfway up the sides of the springform. Bake in the oven for 75-85 minutes, until the edges are set but the center still has a slight jiggle.

When the cooking time is up, turn off the oven and crack the oven door ajar. Let the cheesecake cool in the oven for about 30 minutes, which helps prevent it from cracking due to sudden temperature changes. After cooling, transfer it to a wire rack to cool completely before refrigerating for at least 6 hours or, ideally, overnight.

Once your hot chocolate cheesecake is completely chilled, make the whipped cream topping. In a bowl, beat heavy cream, powdered sugar, and a splash of vanilla extract until medium peaks form, about 3-5 minutes. Spread the fluffy whipped cream evenly over the chilled cheesecake.

To elevate your Hot Chocolate Cheesecake, decorate it with mini marshmallows, chocolate chips, or crushed candy canes for a festive touch.