Spoon that thick leek mixture from your sieve into the pie dish and spread it out evenly. Lay your pastry on top, tuck the ends under then gently score the pastry diagonally with your knife. Add a pinch of salt to your beaten egg then paint this egg wash over the top of your pastry. Pop your pie in the oven for about 35 to 40 minutes or until the pastry is puffed up and golden brown. When the pie is ready, re-heat the gravy and serve with your pie, along with some peas tossed in butter, lemon, salt and pepper and everyone’s happy!