Beat an egg with half the sugar in a suitable bowl. Melt the remaining sugar with the butter in a pan on the stove. Remove from the heat and add the milk, mixed with 1 tablespoon of cold water.
In a deep bowl, sift flour with baking powder and salt. Make a well in the middle add the egg and milk mixture and beat with a nice mixer. Cover the bowl and let it rest for 1 hour or more overnight.
Heat the stove to a relatively low temperature, because the pancakes will quickly burn otherwise. In a frying pan, put the mixture in a few places and shake the pan gently to merge it into a single pancake.