Mix the eggs, flour, sugar and treacle together with a little cold milk. Bring the rest of the milk to the boil and pour it on to the mixture, stirring well. Put in oven dish and dot with butter. Pour the cold water in the middle without stirring. Bake at 325°F, 170°C, gas mark 3 for two hours. This is a traditional dish for Whitsun, but is used for other festivals too.