Preheat your oven to 325°F (163°C) and line a 9-inch springform pan with parchment paper, greasing the sides with butter.

Melt 1 cup of unsalted butter in a saucepan over low heat. Remove from heat, mix in 1 cup of granulated sugar, 2 eggs, and 1 teaspoon of vanilla extract. Stir in 1 cup of unsweetened cocoa powder, 1 cup of all-purpose flour, and 0.5 teaspoon of salt until smooth.

Pour the brownie batter into the prepared pan and bake for 18-20 minutes or until the edges are set.

Beat 16 ounces of cream cheese with 0.5 cup of granulated sugar until smooth. Add 0.75 cup of sour cream, 2 eggs, and 1 teaspoon of vanilla extract, blending until fully combined.

Pour the cheesecake filling over the cooled brownie layer.

Bake the cheesecake layer for 45-50 minutes, until the edges are set and the center is slightly jiggly.

Turn off the oven, open the door ajar, and let the cheesecake rest inside for 1 hour.

Cool the cheesecake at room temperature, then refrigerate for at least 4 hours or overnight.

Heat 1 cup of heavy cream until simmering, pour it over 1 cup of semi-sweet chocolate chips, stir until smooth to create ganache.

Pour the ganache over the chilled cheesecake, then slice and serve with whipped cream or berries.