Make sure the butter and water you are using is cold.
Cut the butter into cubes, add to the flour and rub with your fingertips until you have fine breadcrumb and then make a well in the centre. Add most of the water and a pinch of salt and then mix the dough without overworking it. You just want to bring the ingredients together.
Roll the dough into a ball, flatten slightly and then wrap in cling film. Allow to rest in the fridge for at least 30 minutes. When ready to use, roll the pastry out to a thickness of 5mm.
Preheat the oven to 180'C.
Cut the chicken thighs into 1 inch dice. Roll the chicken in flour, salt and pepper.
Cut the leek into small dice. Peel and dice the carrot. Peel and finely dice the garlic.
Heat a large saucepan over a medium heat and add the butter. Allow to melt and then add the chicken to the pan. Brown the meat on all sides and then add the carrot and cook for 2 minutes before adding the leek. Cook for a further minute and then add the garlic, thyme and chicken stock. Cook for 10 minutes over a medium heat, stirring while the sauce reduces and thickens. Pour the mixture into a pie dish, trim the edges and brush the remaining egg wash over the pastry.
Bake in the oven for 25 minutes or until the pastry is crisp and golden brown.
«The raw pastry will last for approximately four days in the fridge or it can be kept frozen for use at a later date.»