Preheat oven to 180°C.
Grease a large pudding dish.
Add dark chocolate to a small ziplock bag and place in a heatproof bowl. Cover with boiling water and sit until melted. This will only take a minute or two.
In a mixing bowl combine flour, sugar and cocoa and stir to combine.
In another bowl or jug whisk together the milk, melted butter, egg, pinch of salt and vanilla.
Mix the melted chocolate into the egg mixture and whisk well to combine.
Pour egg mixture into the flour mix and stir until combined.
Spread the pudding mixture into your prepared dish.
Combine brown sugar and cocoa and sprinkle over top of the pudding.
Gently pour over boiling water using the back of a spoon to disperse the water.
Bake for 30 minutes or until the pudding is cooked.
Dust with icing sugar (powdered sugar) and serve warm with cream or ice cream.