The basic process is the same when you swap around the ingredients. You can even skip the puff pastry and use mash potatoes or slice some potatoes in to thin crisps and top the pie with them.
I promised an easy chicken pie recipe and here it is.
Heat some oil in a pan and brown off the chicken. Then add the onion and carrot for a further ten minutes. Before adding the bacon and cooking for a further 3 or 4 minutes.
Chuck the flour into the pan and stir through, cooking for about a minute before gradually pouring in the stock.
Pour in the cream and give it all a good suit before adding the peas and mustard and let it simmer for about 5 minutes or so. Season to taste.
Pour the mixture into a large oven-proof dish or and top with the ready-rolled pastry. Brush over the egg and cook in a preheated oven (180 degrees fan oven) for about 25 minutes.
If using leftovers from a roast chicken. Chop up all the bits to bit size chunks and add them just before you add the chicken stock.