2.Heat oil in medium saucepan; cook leek, bacon and mushrooms, stirring, until leek softens. Stir in flour; cook, stirring, until mixture thickens and bubbles. Gradually add stock; cook, stirring, until mixture boils and thickens. Stir in cream, mustard and chicken. Season to taste.
3.Divide mixture into four 1-cup (250ml) ovenproof dishes; top each with a pastry quarter, press around edges to seal.
4.Bake pies about 20 minutes or until browned.
You need to purchase a large barbecued chicken weighing about 900g (1¾ pounds) for this recipe.