Preheat your oven to 325°F (163°C) and grease a 9-inch springform pan. Wrap the pan in heavy-duty aluminum foil to prevent water from leaking in during baking. In a bowl, mix together chocolate wafer crumbs and melted unsalted butter until fully combined. Press this mixture firmly into the bottom of the prepared pan, forming an even layer. Bake for 10 minutes, then remove from the oven and let it cool completely.

Melt the bittersweet chocolate in a double boiler, stirring until smooth and glossy. In a food processor, blend the full-fat cream cheese until creamy and smooth, then add granulated sugar, light brown sugar, and unsweetened cocoa powder. Blend until well combined, pausing to scrape the sides as needed. Next, incorporate the room-temperature eggs, heavy cream, and vanilla extract, blending until just smooth. Finally, fold in the melted chocolate and pour the luscious filling over your cooled crust.

To avoid cracks in your Ultimate Chocolate Cheesecake, place the springform pan inside a larger baking dish. Fill the outer pan with hot water until it reaches about 1 inch up the sides of the cheesecake pan. Carefully transfer both pans to the oven and bake for 1 hour and 10 minutes. The cheesecake should be slightly jiggly in the center when done. Once baked, carefully remove from the water bath and let it cool on a wire rack.

After cooling the cheesecake at room temperature, refrigerate it for at least 6 hours, or preferably overnight. This chilling time allows the flavors to meld beautifully and gives the cheesecake its creamy texture. Keep it covered loosely with plastic wrap or a lid to prevent any unwanted smells from penetrating.

To create the decadent ganache topping, heat the additional heavy cream in a small saucepan over medium heat until just simmering. Pour this hot cream over the chopped semi-sweet chocolate in a bowl. Let it sit for a minute, then whisk until smooth and glossy. Add room-temperature unsalted butter and continue whisking until fully incorporated.

Once the cheesecake has chilled and set, gently pour the smooth ganache over the top, spreading it evenly with a spatula for a beautiful finish. Allow the ganache to set for about 1 hour at room temperature.

When you’re ready to enjoy your Ultimate Chocolate Cheesecake, use a thin-bladed knife to slice through the velvety layers. Wipe the knife between cuts for clean slices, showcasing the creamy filling and glossy ganache. Serve it chilled, paired with whipped cream or fresh berries if desired.