Chicken & Leek Pie with Sour Cream and Parmesan Pastry

Method

1. Start by making your pastry. In a food processor blitz together the flour, butter and parmesan until it resembles breadcrumbs, add sour cream and sea salt and pulse until a rough dough forms. Turn out onto a lightly floured bench and gently bring together until smooth. Shape into a ball and wrap in plastic wrap and allow to rest in the fridge for 20mins. 
2. Preheat oven to 220C. While the pastry is resting, make a start on the filling by heating a large non stick frypan over high heat, add oil and cook chicken in batches, until lightly coloured, remove and set aside. 
3. To the same fry pan add leek and butter, reduce heat and gently sweat down the leek for 3-4 mins. Add garlic, thyme, tarragon and mustard. Stir well to combine. Add chicken pieces and cook for a further 3 mins seasoning well with sea salt and pepper. 
4. Sprinkle over flour and stir to coat all the chicken, cook over low heat for 3-5mins then pour over cream and chicken stock. Bring to a gentle simmer stirring well to incorporate flour and create a silky sauce*. Add filling to a 25cm (1.5L) pie dish. 
5. Remove pastry from fridge and roll out to 5mm thickness in the shape of your pie dish. Cover filling with pastry, crimping the edges. Cut a small hole in the centre of the pastry top and brush with egg wash. Bake for 10mins at 220C and then reduce temperature to 180C and cook for a further 20-25mins. Allow to cool slightly before serving. 

* If the sauce is looking thick, do not worry, this will loosen slightly when pie is baked in the oven.