Heat oven to 180 degrees celsius
Mix together sugar, flour, baking powder, cocoa, and salt
Add in the egg, milk and oil and stir until combined
Place in an oven proof dish
In another bowl combine the cocoa and sugar
Sprinkle the cocoa and sugar mixture over the top of the batter
Pour over the hot water
Bake for around 35 minutes until the cake rises to the top and the sauce is underneath
Serve hot or reheat as desired
