Preheat the oven to fan
180C/ conventional 200C/gas
6. Whizz butter and flour in a
food processor. Add 2 tbsp
water and pulse to a ball.Wrap
the dough in cling film and chill.
Heat the grill to high, brown
the sausages for 5 minutes.
Fry the leeks in the butter for 2-
3 minutes. Sprinkle in flour and
cook, stirring, for 2 minutes.
Take off heat and stir in the
milk. Season, add the mustard
and bring to the boil, stirring.
Cut each sausage in five at
an angle and pile into a 1.2 litre
dish. Stir the parsley into the
leek sauce and pour over.
Roll out the pastry and cut out
a shape 2.5cm larger than the
dish.Re-roll trimmings to make
a 2.5cm strip. Brush the rim of
the dish with water and lay the
strip on top. Lift the rest on top,
press to seal and crimp edges.
Bake for 25 minutes.