Method

​1 Pastry: In a bowl, rub the gluten-free flour and butter together until they resemble fine breadcrumbs. Add a pinch of salt and mix. Beat the egg in a separate jug, then gradually add the egg into the flour and butter. With your hand bring together the pastry into a ball. Place in a plastic bag or wrap in cling film and put into the fridge for 30 minutes. You can also do this in a food processor if you have one.

2 Filling: Heat the oil in a frying pan, add the chicken and fry until the chicken begins to turn white. Remove the chicken from the pan and set aside. Add the onion and mushrooms to the same pan and cook for 2-3 minutes or until softened. Remove from the heat and set aside with the chicken while you make the sauce.

3 Melt the butter in a saucepan, stir in the gluten-free flour and cook for about three minutes, stirring constantly until it has formed a thick smooth paste (this is called a roux). Mix the milk and stock together in a jug, then season with the salt and pepper. Pour the liquid slowly into the flour mixture, whisking all the time until smooth. Simmer over a gentle heat, stirring constantly, for about five minutes or until the sauce has thickened.

4 Stir in the chopped parsley and pour the sauce over the chicken and mushroom mixture. Mix well, then spoon into a pie dish and leave until completely cool.

5 Preheat the oven to 200°C/fan 180°C/gas mark 6.

6 Remove the pastry from the fridge. Roll out the pastry between 2 sheets of clingfilm until it is the thickness of a pound coin (I roll the pastry out within the clingfilm so it does not stick to the rolling pin or table). Lay the pastry on top of the mixture, press down the edges and trim. Brush the top of the pie with the beaten egg and cut some leaf shapes out of the left-over pastry to decorate the top of the pie.

7 Make two or three slits in the top of the pie to allow steam to escape and then bake in the oven for 20-25 minutes or until golden-brown on top.