Creamy Chicken Pot Pie

olive oil and butter, for frying
salt and milled pepper
500g deboned chicken thighs, diced
2 leeks, sliced
2 celery sticks, sliced
1 packet (250g) white or brown mushrooms, sliced
2 cloves garlic, chopped
2 Tbsp (30ml) thyme leaves
1/2 cup (125ml) white wine
1 cup (250ml) chicken stock
1 tub (250ml) cream
1 small packet (80g) baby spinach, blanched and chopped or frozen vegetable mix
1 cup (250ml) fresh or frozen peas
1 roll puff pastry, defrosted, divided into 4
1 extra-large egg yolk, beaten

Cooking Instructions
Preheat oven to 220 C.
Heat the oil and butter in pan and lightly saute the seasoned chicken until browned. Remove the cooked chicken from the pan and set aside.
Fry the leeks, celery and mushrooms until soft but be careful not to brown too much. Add the chopped garlic and fry for another minute.
Toss in the thyme leaves, wine, chicken stock, cream and browned chicken. Let this simmer for 25 minutes - the liquid should reduced by about half. Stir through wilted spinach and peas.
Spoon filling into 4 ramekins /small pie dishes and cover each with pastry. Crimp edges with a fork and make a few slits in the pastry to allow steam to escape from the chicken pies while they are baking.
Brush the tops of the pies with egg yolk and bake for 20 minutes or until the pastry has gone that delicious golden colour.