Sieve the flour and salt into a bowl, make a well in the centre.
Add the egg and milk, gradually incorporating the flour from the sides whisk to a smooth batter then mix in the butter. For best results cover with a damp cloth and allow to rest for 2 hours.
Heat a non-stick frying pan and add about 1tsp oil. Pour in a small ladle full of batter, turning the pan around and around until the bottom of the pan is covered with a thin layer of the mixture.
When bubbles form on top, flip the pancake over and brown the other side. Keep warm in a low oven while continuing to make pancakes with remaining batter.