Leek pie

Preparation:

Preparation: Heat the oven to 200 degrees (thermostat 6). Wash the white stems of the leeks and cut them into thin slices. Melt the butter in a large saucepan and add the leeks. Mix well and simmer them for about fifteen minutes until tender. In the meantime, flour the work surface and roll out a rectangle of puff pastry measuring 30 x 25 cm. Fold this rectangle in half lengthwise. Pass the rolling pin over it, without pressing too hard, to eliminate the air bubbles. Weld the edges of the dough by pressing well on the two thicknesses. Place the dough on a slightly damp baking tray, pierce the entire surface with the prongs of a fork and cook in the oven for ten minutes. Break the egg into a bowl, add a pinch of salt and beat it with a fork. Remove the pastry from the oven and brush the surface with the beaten egg, pressing it lightly onto the pastry. Put back in the oven and leave to brown for ten minutes. Add the cream and nutmeg to the leeks, salt and pepper and mix well. Keep warm. To serve, place the puff pastry on a serving plate and place the leek preparation on top.