Sift the flour and salt into a mixing bowl, then make a well in the centre. Crack the egg into the well, then add the melted butter and half the milk. Gradually stir the liquid into the flour with a wooden spoon, until all the ingredients have been incorporated. Beat well to make a smooth batter. Stir in the remaining milk and let stand for about 30 minutes. Stir again before using.
To make the pancakes, heat a small, heavy-based frying pan until very hot, then turn down the heat to medium. Lightly grease with oil and ladle in enough batter to coat the base of the pan thinly (two-three tablespoons), tilting the pan so the mixture spreads evenly.
Cook over a medium heat for one to two minutes, or until the batter looks dry on top and begins to brown at the edges. Flip the pancake with a spatula, and cook the second side.
Turn out on to a plate, smear with a little butter, sprinkle with sugar and, finally, splash with a squeeze of lemon juice – or simply with Nutella.