1. Prepare the dough.
2. In a cup, dissolve the yeast in 3 tablespoons of warm water.
3. In a bowl, mix the flour and salt. Make a well in the center and pour the yeast and 10 cl of warm water.
4. Work the dough on a floured surface until it becomes smooth. Let it rise for 3 hours at room temperature.
5. Take the butter out of the refrigerator to soften. Grease a cake pan.
6. Once the dough has tripled in volume, roll it out on a floured surface into a square shape about 1 cm thick.
7. Spread butter on it and sprinkle with sugar up to 3 cm from the edges.
8. Fold the dough in three. Roll it out very thinly with a rolling pin. Fold it in three again. Roll it out into a round shape.
9. Place the dough in the greased cake pan and let it rest for 30 minutes.
10. Preheat the oven to 210°C (thermostat 7).
11. Bake in the oven for 35 minutes. After 10 minutes, baste the cake every 5 minutes with the melted butter.
12. Let it rest for 15 minutes before removing from the pan. Sprinkle with 3 tablespoons of sugar. Serve the kouign aman warm.