Preheat your oven to 180°C (160°C for fan assisted ovens) / Gas Mark 4.
Mix the brownie mix, egg, water, oil, together until well blended.
Spread the mixture evenly into the greased rectangular tin.
Bake in the centre of the oven for around 20-25 minutes or until a rounded knife, inserted comes out almost clean. Leave to cool in the tin. Meanwhile, make the espresso and while the brownie is still warm, trickle over the sponge. Allow to cool, then put in the fridge for at least an hour.
Whisk the cream, mascarpone, sugar and Marsala wine in a bowl until combined. The mixture should be thick and creamy.
Slice the brownie into 8 pieces and carefully transfer onto a small plate as they will be very moist.Devine!
Pipe the cream on top of each brownie before dusting with cocoa powder.