Preheat the oven to 220C. Pour the contents of the can into a shallow oven dish and wrap tightly with aluminium foil. Once wrapped put the shallow dish inside a bigger oven tray which you can fill half way up the other dish with hot water and place in the oven. Leave in the oven for roughly 1 to 1.5 hrs and check the water level in your oven dish every once in a while and add where needed.
Remove the dish from the oven and once to your preferred color, whisk until the cream is smooth and leave to cool!