Pâte à crèpes (pancake mix)

Melt the butter. Pour the flour, sugar, salt, and eggs into a bowl, add the milk, and mix carefully with a whisk, then add the butter. Leave the mixture to rest for 1 hour. Heat a frying pan with a little oil, pour in a ladleful of the pancake mixture, cook until golden brown, then turn. Cook for a few moments longer, then repeat with the remainder of the pancake mix.