Pour all of the ingredients into a 2-quart/2 liter ceramic casserole dish. Give it a stir. Turn the oven to 80°C/180°F, place the porridge into the oven, shut the door, let it be overnight.
Pour 2 cups of frozen berries into a wide, shallow bowl: blueberries, bilberries, raspberries, strawberries, blackcurrant, blackberries…whatever you have! I like a combination of berries, myself. Place the berries in the fridge overnight to thaw.
In the morning, pull the porridge from the oven and serve topped with berries and accompanied by a steaming cup of coffee or tea and the morning paper.