Preheat your oven to 170°C and grease/line a 20cm square cake tin.
Melt the chocolate and butter in a bowl over a pan of simmering water.
Remove from heat and allow the mixture to cool slightly.
Whisk eggs, sugar, and espresso together in a separate bowl until combined.
Sift in the flour and fold in the chocolate mixture.
Beat the cream cheese, sugar, egg, and orange zest together until smooth.
Spoon brownie batter into the tin and top with cheesecake mixture.
Swirl with a knife to create a marble effect and bake for 25-30 minutes.
Cool completely in the tin before cutting into 16 squares.