Preheat your oven to 350°F (175°C) and line a square baking pan with parchment paper, leaving some overhang for easy removal.

In a microwave-safe bowl, gently melt the butter and chopped dark chocolate together, stirring every 20 seconds until glossy.

Whisk sugar into the melted chocolate mixture until it dissolves. Add eggs one at a time, whisking briskly, then stir in vanilla extract.

Gently fold the sifted flour into the wet ingredients using a spatula, mixing just until combined.

Beat the softened cream cheese until smooth. Gradually add sugar, then the egg and vanilla, mixing until just combined.

Pour half of the brownie batter into the prepared pan. Dollop the cheesecake mixture over it. Spoon the remaining brownie batter on top and swirl with a knife.

Place in the oven for 40-45 minutes, until the edges are set with a slightly jiggly center.

Heat heavy cream until simmering. Pour over chopped dark chocolate, let sit for a minute, then stir until smooth.

Once brownies are cool, pour the ganache over the top. Chill until set and cut into squares to reveal the luscious layers.