Preheat your oven to 175°C (350°F). Lightly oil a 9-inch brownie pan and line it with parchment paper.

Combine dark chocolate and unsalted butter in a heatproof bowl. Melt using a double boiler or microwave until smooth.

In a mixing bowl, whisk together room temperature eggs, granulated sugar, and brown sugar for 5-7 minutes until pale and airy.

Pour the melted chocolate and butter mixture into the egg mixture, mixing on low speed until fully combined.

Sift all-purpose flour, cocoa powder, and salt into the wet ingredients and fold until just combined.

Pour 90% of the brownie batter into the prepared pan and reserve the remaining for topping.

In a separate bowl, whip cream cheese with granulated sugar until smooth. Add an egg and vanilla extract, mixing thoroughly.

Pipe or spoon the cheesecake layer over the brownie batter. Swirl reserved brownie batter on top for marbling.

Bake for 35-40 minutes until edges are set and center looks slightly gooey.

Remove from oven and let cool completely in the pan before slicing.