Grease 1 large rectangular or 6 x 9cm round pie dish.

Preheat oven 200c.

Melt butter over a medium high heat. Suate bacon until it has just browned and set aside.

Add the chicken to pan and brown the chicken pieces for about 4 minutes. Set aside

Lower the heat, add the leeks and thyme to the pan and cook until softened. Transfer the mix to a bowl and set aside.

Add the flour to remaining butter in the pan to form a Roux. Cook for 2 minutes,stirring constantly. Slowly add chicken stock, 1 cup at a time, to create a thick sauce.

Add the bacon, chicken and the leeks to the sauce. Cook for 20 minutes over a medium heat, stirring occasionally to prevent the sauce from catching. The mixture should be thick enough for the chicken and leeks not to sink to the bootom. Add the mustard and parsley and season with salt and pepper. set aside to cool.

Fill the pastry lined dish to the rim with the chicken filling. top with grated cheese.

Cut the remaining pastry into strips to make a lattice lid for the lid.

Paint the pastry lid with egg wash.

Bake for 25 minutes or until golden brown.