Preheat the oven to 180 °C. Line a 20cm square pan with baking paper, leaving an overhang of paper on both sides (this eases lifting the baked brownies out of the pan in one piece). Lightly grease the paper with cooking spray.
Brownie batter: Place the butter and chocolate chips in a large bowl and microwave in 30 second increments until just melted, or melt in a double boiler over lightly simmering water. Stir until smooth and cool slightly, around 5 minutes. Whisk in the sugar, then the eggs one by one and finally whisk in the vanilla extract. Add the flour, cocoa powder, coffee granules (if used) and salt to the bowl. Stir gently until just combined. Reserve ¼ of the brownie batter and spread the remaining ¾ of the batter into the pan.
Cheesecake batter: In a bowl beat the cream cheese and sugar with a mixer for 2-3 minutes until lump-free and creamy, then add the egg and vanilla extract, beat until smooth. Pour the cheesecake batter over the brownie batter in the pan.
Add 15 ml very hot water to the reserved brownie batter and stir until smooth. Dollop the brownie batter over the cheesecake, swirling the two batters together with a skewer or knife.
Bake for 30-35 minutes or until a testing skewer inserted into the centre comes out clean. Cool completely before lifting the brownies from the pan. Cut into squares and devour.