Sprinkle the sugar over the cake mixture and dot
with butter. Pour over the boiling water (yes really!) and transfer to the oven. Set the time for 45 minutes, though you might find the dessert needs 5 or 10 minutes more. The top of the dessert should be springy and spongy when it's cooked; underneath, the butter, dark brown sugar and boiling water will have turned into a rich, sticky sauce
. Serve with vanilla ice cream
, creme fraiche or heavy or light cream
, as you wish.