Pour the flour in a bowl and mix it with salt and sugar. Add the eggs and mix again.
Progressively incorporate the milk and water into the mixture until you get a homogenous dough. Let the dough rest for 1h.
In a crepe pan, melt a knob of unsalted butter and pour a ladle of dough. When the crepe is ready, add few knobs of salty butter on it and close the crepe.
Dust with sugar and serve it.