Put the potatoes and onions in a pan of water . Bread my to the boil and cook until soft . Drain and mash , add in all but a few sprinkles of cheese . Season with salt and pepper . Leave to cool

Heat oven to 200c

Roll out the pastry . Using a side plate or saucer cut 4 circles

Put piles of the potato mix on half of the circle. Brush the outer rim with beaten egg and bring over the top . Seal and twist the edges .

Put on a lined baking tray . Brush with egg and bake for 25-30 minutes. Serve hot or cold