Preheat your oven to 325°F (163°C). Grease a 9-inch springform pan thoroughly and wrap it in aluminum foil.

In a mixing bowl, combine the chocolate wafer crumbs with melted unsalted butter until resembling wet sand. Press into the bottom of the pan, bake for 10 minutes.

Set up a double boiler and melt the coarsely chopped bittersweet chocolate, stirring constantly until smooth.

Blend the full-fat cream cheese in a food processor until smooth. Gradually add the granulated sugar, light brown sugar, and unsweetened cocoa powder until well combined.

With the food processor running, add the large eggs and heavy cream one at a time, blending just until combined.

Gently fold the slightly cooled melted chocolate and vanilla extract into the cream cheese mixture until thoroughly combined.

Place the springform pan in a larger baking dish and fill with hot water up to 1 inch on the sides.

Bake for 1 hour and 10 minutes. The cheesecake is done when the edges are set, but the center jiggles slightly.

Once baked, let cool in the oven with the door cracked for about an hour, then cool completely on a wire rack.

To make ganache, heat heavy cream until simmering, pour over chopped chocolate and whisk until smooth. Optional: add butter.

Pour the ganache over the chilled cheesecake and let set at room temperature for about 30 minutes before slicing.