Sift the flour into a large bowl, add the butter and rub in with your fingertips until the mixture resembles fine breadcrumbs.
Stir in a pinch of salt, and then add 2-3 tbsp of water and mix together to form a firm dough. Knead the dough briefly and gently on a floured surface. Wrap in cling film and allow to rest for a minimum of 1 hour and prepare the pie filling while the pastry in resting.
Place the butter, diced carrot, diced leek, diced onion, garlic clove and diced chicken thighs into a pot and cook over a medium heat for fifteen minutes.
Add in 2 tbsp. of flour and mix until combined.
Add in the white wine and mix well, allow the mixture to cook for 2 minutes over a medium heat.
Add in the chicken stock and half of the cream, and cook for 2 minutes, mixing vigorously, then add in the remaining cream and bring to a simmer.
Add in the peas, season the mix and set to one side.
Pre-heat the oven to 190C / Fan 170C / Gas Mark 5. Remove the pastry from the fridge, flour the bench and the rolling pin, roll the pastry into a large round shape – about 3 inches larger than the base.
Brush your tin with butter, and place the pastry into the tin, then line the pastry with grease proof paper and bake for 15 minutes until it becomes slightly coloured around the edges, remove the grease proof paper to expose the base and bake for a further 5 minutes. Set aside and allow to cool.
Pour the mix into the base of the pastry and smooth out.
Peel and slice the potatoes thinly, then lay them on top starting at the edge of the pie, overlapping until you come to the centre of the pie – don’t allow any gaps.
Brush the potato topping with butter, and then place the pie in the oven at 190C / Fan 170c/ Gas Mark 5 and cook for 35 mins until the potato topping becomes golden in colour.