Using a floured surface, roll out the pastry to 3-4mm thick and at least 30mm larger on all sides of the dish shape you intend to use. Cut a long strip the width of the pie dish rim approx 1cm, brush with the egg, and fix pastry strip to the edge of the pie dish. Brush the strip again with egg, then using a rolling pin to lift the remaining pastry over the pie. Gently crimp around the edges with a fork and trim with a sharp knife. Brush lightly with egg to glaze. If you would like to decorate the top, you can use any of the pasty off-cuts to create leaves or shapes, press them onto the glazed top, and re-glaze these, finally, a gentle sprinkle of dried thyme or italian herbs, freshly ground sea salt and black pepper on top. Last, but not least, put a small knife incision or hole in the centre of the crust to allow the steam to escape.