Raise the yeast in a cup with sugar and a little warm water. Place in a warm place until frothy.
Beat the egg omelette with salt and a pinch of sugar. Stir in the flour by hand. Pour the yeast and butter. Mix until the dough comes away from the sides of your bowl.
Cover with a damp cloth and place 1 hour in a warm place. Butter a pie pan and spread out dough. Let rest in a warm, with the cloth at the top, 30 minutes to 1 hour.
Sprinkle with sugar and bake pie 15 to 20 minutes at 200 ° C (gas mark 6-7). At the exit of the oven, spread butter with a knife on the entire surface of the pie.
Let cool and enjoy !